Defendant contends that he has been placed in double jeopardy by being twice tried for the same capital offense of murder. In this connection he contends that Judge McLean erred in entering an order declaring a mistrial without defendant’s consent at the 25 May 1970 Session of Madison Superior Court, and that he erred in altering the order of mistrial of 1 June 1970 and in signing the same on 28 January 1971.
 The burden is upon defendant to sustain his plea of double jeopardy. He failed to plead double jeopardy and to offer supporting evidence thereon, and he is therefore deemed to have abandoned the plea of double jeopardy and to have relied solely on his plea of not guilty. State v. Baldwin, 226 N.C. 295, 37 S.E. 2d 898; State v. Davis, 223 N.C. 54, 25 S.E. 2d 164; State v. King, 195 N.C. 621, 143 S.E. 140; State v. Smith, 170 N.C. 742, 87 S.E. 98; State v. Ellsworth, 131 N.C. 773, 42 S.E. 699.
On 25 February 1971, three months after expiration of the time allowed by the trial judge for submitting the case on appeal and 28 days after Judge Thornburg settled the case on appeal, counsel for defendant filed a motion in which it was stated that counsel was employed only two days before the second trial commenced and therefore was not prepared to enter the plea of double jeopardy. By his motion defendant contends that Judge McLean was in error in declaring a mistrial because there was not sufficient evidence presented to the court upon which the court could base a determination that the ends of justice could not be carried out because the jury had been tampered with, and because the court failed to examine the juror involved. Defendant prayed that Judge McLean’s order of 1 June 1970 be declared *344in error and that the verdict and judgment of the court at the 28 September 1970 session of Madison be declared null and void as in derogation of defendant’s constitutional rights not to be tried twice for the same offense.
Although defendant appears to have abandoned the plea of double jeopardy, we choose to consider the merits of this constitutional question because of the seriousness of the crime here involved.
 It is a fundamental principle of the common law, now guaranteed by our federal and state constitutions, that no person can be twice put in jeopardy of life or limb for the same offense. State v. Hicks, 233 N.C. 511, 64 S.E. 2d 871; State v. Crocker, 239 N.C. 446, 80 S.E. 2d 243; State v. Prince, 63 N.C. 529; N.C. Const. Art. I, § 17; U. S. Const. Amend. V.
 Jeopardy attaches when a defendant in a criminal prosecution is placed on trial: (1) on a valid indictment or information, (2) before a court of competent jurisdiction, (3) after arraignment, (4) after plea, and (5) when a competent jury has been empaneled and sworn. State v. Birckhead, 256 N.C. 494, 124 S.E. 2d 838.
 In an instant case it is clear that the elements of jeopardy are present. Even where, as here, all the elements of jeopardy appear, a plea of former jeopardy will not prevail where the order of mistrial was properly entered for “physical necessity or for necessity of doing justice.” We therefore must consider whether Judge McLean, without defendant’s consent, lawfully ordered a mistrial and discharged the jury before verdict.
In State v. Tyson, 138 N.C. 627, 50 S.E. 456, it is stated:
“It is well settled, and admits of no controversy, that in all cases, capital included, the court may discharge a jury and order a mistrial when it is necessary to attain the ends of justice. It is a matter resting in the sound discretion of the trial judge, but in capital cases he is required to find the facts fully and place them upon record so that upon a plea of former jeopardy, as in this case, the action of the court may be reviewed.”
Accord: State v. Ellis, 200 N.C. 77, 156 S.E. 157; State v. Beal, 199 N.C. 278, 154 S.E. 604; State v. Cain, 175 N.C. 825, 95 S.E. *345930; State v. Upton, 170 N.C. 769, 87 S.E. 328; State v. Wiseman, 68 N.C. 203.
In the case of State v. Crocker, supra, Bobbitt, J. (now C. J.) stated:
“The two kinds of necessity, i.e., ‘physical necessity’ and the ‘necessity of doing justice’ were so classified by Boyden, J., in S. v. Wiseman, 68 N.C. 203. As to ‘physical necessity,’ he said: ‘One class may not improperly be termed physical and absolute; as where a juror by a sudden attack of illness is wholly disqualified from proceeding with the trial; or where the prisoner becomes insane during the trial, or where a female defendant is taken in labor during the trial.’ As to ‘necessity of doing justice,’ he said that this arises from the duty of the court to ‘guard the administration of justice from fraudulent practices; as in the case of tampering with the jury, or keeping back the witnesses on the part of the prosecution.’
“It will be observed that ‘the necessity of doing justice’ is not an expression connoting a vague generality but one that relates to a limited subject, namely, the occurrence of some incident of a nature that would render impossible a fair and impartial trial under the law. In S. v. Wiseman, supra, the basis for mistrial was ‘tampering with the jury.’ In S. v. Bell, 81 N.C. 591, and in S. v. Washington, 89 N.C. 535, 45 Am. Rep. 700, a juror had fraudulently procured himself to be put on the jury for the purpose of acquiting the defendant in a trial for murder. In S. v. Cain, 175 N.C. 825, 95 S.E. 930, a juror had given a false answer to the solicitor bearing upon his fitness and qualifications to serve as a juror. ...”
 Judge McLean’s findings of fact are to the effect that one Andrew Jack Thomas, during a weekend recess of the trial, in his truck carried Charles Wayne Goforth, a member of the jury trying defendant, to within 100 yards of defendant’s trailer home, and at that time juror Goforth instructed Thomas to go to defendant’s trailer and tell defendant that juror Goforth wanted to see him on a nearby wooded logging road. Juror Goforth then proceeded down the path into the woods. Thomas delivered the message and returned to his parked truck, and he shortly thereafter saw a black automobile proceed down the *346same trail taken by juror Goforth. Defendant is the owner of a black Oldsmobile automobile.
We conclude that these findings of the court, without considering the findings as to the incident in Henderson Cafe, are sufficient to support Judge McLean’s conclusion that juror Goforth had “been tampered with and would be unable to render a fair and impartial verdict.”
 Defendant, however, further argues that the evidence presented to the court was not sufficient to support the court’s findings of fact. There is no evidence on this question in the record. Admittedly this Court would have been more enlightened had the record contained the testimony of the witnesses1 heard by the trial judge on the question of mistrial; however, it is well recognized that a silent record supports the presumption that the proceedings in the court below were regular and free from error. State v. Mullis, 233 N.C. 542, 64 S.E. 2d 656. Further, it was the duty of the defendant to see that the record was properly made up and transmitted, and when the matter complained of does not appear of record, defendant has failed to show prejudicial error. State v. Childs, 269 N.C. 307, 152 S.E. 2d 453; State v. Ellis, supra.
[8, 9] Neither do we find it prejudicial error that the order declaring a mistrial was not signed in term time. The stated purpose of a written order finding facts when a mistrial is ordered in a capital case is to furnish a basis for appellate review. State v. Tyson, supra. In instant case the order finding facts and ordering a mistrial was signed long before defendant had raised the issue of double jeopardy, and the order was in the record in ample time for defendant to prepare his case on appeal. The additions found in the signed order merely gave a meaning to the sentence which had evidently been clouded by an inadvertent omission. It is therefore manifest that no prejudicial error resulted from the addition to the order or because the order was signed after adjournment of the 25 May 1970 session.
 We find no merit in defendant’s further argument that Judge McLean erred in not examining the witness Goforth before he ordered a mistrial. In many instances a trial judge is warranted in examining jurors to see if some untoward incident has so affected them that they cannot render a fair and impartial *347verdict. In this case such an examination of the juror whose misdeeds allegedly created the necessity for a mistrial would be a patently vain exercise.
[I] Judge McLean’s findings show such absolute necessity for the entry of an order of mistrial that, in law, there was no trial of defendant at the 25 May 1970 session. We therefore hold that defendant was not put in double jeopardy by virtue of the proceedings held at the 25 May 1970 session of Madison Superior Court.
[II] Defendant next contends that two photographs of Reeves’ body were erroneously admitted into evidence because they were inflammatory and were introduced without reason since defendant had admitted the cause of Reeves’ death.
Properly authenticated photographs of the body of a homicide victim may be introduced into evidence under instructions limiting their use to the purpose of illustrating the witness’ testimony. Photographs are usually competent to be used by a witness to explain or illustrate anything that it is competent for him to describe in words. The fact that the photograph may be gory, grewsome, revolting or horrible, does not prevent its use by a witness to illustrate his testimony. State v. Atkinson, 275 N.C. 288, 167 S.E. 2d 241; State v. Porth, 269 N.C. 329, 153 S.E. 2d 10; State v. Gardner, 228 N.C. 567, 46 S.E. 2d 824.
Defendant’s admission as to the cause of death did not preclude the State from introducing the photographs of Reeves’ body. The admission that Reeves’ death was caused by a gunshot wound did not relieve the State of the burden of proving its entire case beyond a reasonable doubt as long as defendant stood on his plea of not guilty. It was an essential part of the State’s theory that the victim was shot by someone on decedent’s right. The photographs in question were properly used to illustrate testimony of Drs. Duck and Lacey that the fatal bullet had, in fact, entered deceased’s right side and exited on his left. The State could, therefore, select the method of proving its case subject to the enforcement of the rules of evidence and fair play by the trial judge. State v. Vestal, 278 N.C. 561, 180 S.E. 2d 755; Rivers v. United States, 270 F. 2d 435, cert. den. 362 U.S. 920, 4 L. Ed. 2d 740, 80 S.Ct. 674; People v. Dunn, 29 Cal. 2d 654, 177 P. 2d 553; Commonwealth v. Novak, 395 Pa. 199, 150 A. 2d 102; State v. Leland, 190 Ore. 598, 227 P. 2d 785.
*348We are aware of the holdings in the cases of State v. Mercer, 275 N.C. 108, 165 S.E. 2d 328, and State v. Foust, 258 N.C. 453, 128 S.E. 2d 889. Both of these cases turn on the introduction of an excessive number of photographs having no probative value. Here, the trial judge allowed only two properly authenticated photographs to be introduced under instructions to the jury that they were admitted for the sole purpose of illustrating the witnesses’ testimony. There was no error in the admission of the two photographs.
 Neither do we find prejudicial error in the admission into evidence of the bloodstained skirt worn by the witness Blanche Cutshall on the night of the homicide.
Mrs. Cutshall, in part, testified: “He shot in — shot into the car there . . . Jack fell over on my legs. . . . With reference to the marks or spots on the bottom portion of this skirt, his head would have been right on my legs where this — this is— where the blood is, because he fell over on me there.”
It is not error to permit clothing of a victim or other articles to be introduced into evidence which bear stains or appear corroborative of the theory of the State’s case, or which “enable the jury to realize more completely the cogency and force of the testimony of the witness.” State v. Atkinson, supra; State v. Speller, 230 N.C. 345, 53 S.E. 2d 294; State v. Vann, 162 N.C. 534, 77 S.E. 295; State v. Wall, 205 N.C. 659, 172 S.E. 216. The cases above cited relate to introduction of the bloodstained and torn clothing of deceased victims of the crime. Certainly the bloodstained skirt of a living witness would not create such prejudice as would the torn or bloodstained clothing of a deceased victim.
 Defendant next contends that the trial court erred in permitting Sheriff Roy Roberts and Blanche Cutshall to testify that they heard Dewayne Cutshall make a statement to the effect that defendant was at Riverside establishing his alibi, after Dewayne Cutshall had denied making such statement under cross-examination.
The State recalled Sheriff Roberts, who testified over objection: “We was talking about where he possibly could be. Dewayne says, I know where he is. He’s down at Riverside making up alibis.” The State also recalled Blanche Cutshall, who testified over objection that she heard her son Dewayne *349state in Sheriff Roberts’ presence that his daddy was “probably at Newport establishing an alibi . ” (Emphasis ours.)
When a cross-examiner seeks to discredit a witness by showing prior inconsistent statements or other conduct, the answers of the witness to questions concerning collateral matter are generally conclusive and may not be contradicted by extrinsic testimony. State v. Poolos, 241 N.C. 382, 85 S.E. 2d 342; State v. Broom, 222 N.C. 324, 22 S.E. 2d 926; State v. Gardner, 226 N.C. 310, 37 S.E. 2d 913; State v. Jordan, 207 N.C. 460, 177 S.E. 333; Stansbury, North Carolina Evidence § 48. This rule is subject to the following exception: Where a party cross-examines an adverse witness as to collateral matters which tend to show the partiality or bias of the witness toward the cross-examiner’s adversary, or which shows the witness’ hostility toward the cross-examiner’s cause, the cross-examiner is not bound by the witness’ answer denying partiality or hostility. The cross-examiner, after putting the witness on notice, is at liberty to contradict the witness by extrinsic evidence. State v. Hart, 239 N.C. 709, 80 S.E. 2d 901; State v. Roberson, 215 N.C. 784, 3 S.E. 2d 277; State v. Spaulding, 216 N.C. 538, 5 S.E. 2d 715; State v. Rowell, 244 N.C. 280, 93 S.E. 2d 201; State v. Patterson, 24 N.C. 346; 58 Am. Jur., Witnesses, § 715.
In the case of State v. Taylor, 250 N.C. 363, 108 S.E. 2d 629, the Court considered the proper test for determining whether contradictory testimony relates to a material or collateral matter, and stated:
“ . . . [D] efendant quotes Stansbury, North Carolina, Evidence, § 48(3) : ‘The proper test would seem to be whether the evidence offered in contradiction would be admissible if tendered for some purpose other than mere contradiction; or, in case of prior inconsistent statements, whether evidence of the facts stated would be so admissible.’ The ‘proper test,’ as so defined, is amply supported by cases cited by Professor Stansbury and by defendant.”
Assuming, arguendo, that Dewayne made the statement attributed to him under the circumstances related, it is obvious that such statement would be, at most, a speculative, conjectural expression of opinion completely lacking in probative value towards establishing a material fact in the case. The statement would not be admissible for any purpose other than contradic*350tion, and is therefore collateral. Thus, when Dewayne Cutshall denied making the collateral statement, the State was bound by his answer and could not offer extrinsic evidence for the purpose of impeaching the witness as to his prior inconsistent statements. Yet, the admission of the incompetent testimony of Blanche Cutshall and Sheriff Roy Roberts contradicting- Dewayne’s denial gave the State the benefit of evidence which tended to weaken and undermine defendant’s sole defense of alibi. The admission of the evidence is rendered highly prejudicial for the reason that its weight would be greatly magnified in the eyes of the jury because the damaging statements allegedly came from defendant’s own child who was a witness for the defense.
The State did not contend — and we think properly so— that the contradictory evidence was admissible to show bias, temper or disposition of the witness. Assuming that the statement was made and that its content was such as to show bias or partiality, it could only be interpreted to show bias or partiality in favor of the State and against defendant.
Defendant did not request, nor did the judge on his own motion give, instructions restricting the evidence to impeachment. Had the instructions been given, the incompetent evidence would not have been rendered competent; nor is it probable that its highly prejudicial effect would have been diluted in the eyes of the jury by such instructions.
Error in the admission of this evidence requires a new trial.
Since there must be a new trial, we do not deem it necessary to discuss defendant’s assignment of error concerning hearsay testimony of Bobby Stinson. The answer complained of was clearly hearsay, but was “invited” by defendant’s counsel. In all probability this occurrence will be avoided at the new trial. State v. Burton, 256 N.C. 464, 124 S.E. 2d 108; State v. Williams, 255 N.C. 82, 120 S.E. 2d 442; State v. Sutton, 225 N.C. 332, 34 S.E. 2d 195.