The defendant’s first contention on appeal is that there was error in admitting testimony as to statements made by the defendant during periods of custodial interrogation. In this we find no merit.
The defendant’s motion to suppress evidence of all such statements made by her was heard, prior to trial, by Judge God-win, at which hearing both the State and the defendant presented evidence. As to the statements so made by the defendant and the circumstances and conditions under which they were made, there is no substantial variance between the evidence so introduced at the pretrial hearing on the motion to suppress and that introduced before the jury at the trial.
*424At the conclusion of the hearing of the motion to suppress, Judge Godwin made numerous and detailed findings of fact. Each of these findings is fully supported by evidence so offered at the hearing. Although the testimony so given by the investigating police officers and that so given by the defendant conflicted in some respects, in such a situation the findings made by the hearing judge and so supported by evidence are conclusive on appeal. State v. Thompson, 287 N.C. 303, 317, 214 S.E. 2d 742 (1975); State v. Blackmon, 284 N.C. 1, 9, 199 S.E. 2d 431 (1973); State v. Gray, 268 N.C. 69, 78, 150 S.E. 2d 1 (1966), cert. den., 396 U.S. 934, 90 S.Ct. 275, 24 L.Ed. 2d 232; Strong, N.C. Index 3d, Criminal Law, § 76.10.
These findings of fact included the following (summarized and renumbered): (1) The defendant’s initial statement to the effect that an unknown intruder entered the trailer, shot the child while the defendant lay asleep on a couch in the living room and then fled from the trailer was made to the officers when they first arrived at the trailer and was made voluntarily; (2) when Deputy Stewart, shortly thereafter, took the defendant from the trailer out to his patrol car for an interview, he advised the defendant of her constitutional rights in accordance with the Miranda formula; (3) the defendant affirmatively indicated that she understood her rights and was willing to make a statement and answer questions without an attorney being present to advise her; (4) repeatedly thereafter (on five separate occasions), as the interviewing process was resumed by the officers following interruptions, the defendant was again so advised of her constitutional rights pursuant to the Miranda formula and signed written waivers thereof; (5) the interviewing process was frequently interrupted and the defendant on several occasions returned to her home, or to the home of her parents, no interviews taking place on February 29, March 1 or March 2; (6) during other interruptions of the interviewing process, the defendant was offered, and given, food and drink and opportunities to retire to the rest room.
These findings of fact fully support the conclusions of the hearing judge to the effect that: (1) The defendant was not in custody at the time of her initial statement to the officers shortly after their arrival at her trailer home; (2) all statements by the defendant to the officers, both inculpátory and exculpatory, were made after she was advised of her constitutional rights and were *425“freely, understandingly, knowingly, and voluntarily made with full knowledge” of such rights, which rights she “at those times knowingly, understandingly, and voluntarily waived.” These conclusions further support the final conclusion of the hearing judge that the statements made by the defendant to the officers “are legally competent to be received in evidence against the defendant upon her trial.” Consequently, there was no error in admitting the officer’s testimony concerning these statements.
 The defendant’s second contention on appeal is that the trial court erred in failing to give to the jury instructions with reference to insanity, though requested to do so by the defendant. In this contention we find no merit.
A careful study of the entire record reveals no evidence whatever to indicate that the defendant was insane. Her defense at the trial was not insanity but was that it was not she who shot and killed the child. Dr. Rollins, the expert psychiatrist called as a witness in her behalf, expressly testified, “I have made no evaluation of the sanity of the defendant.” The fact that the defendant, if the evidence for the State be true and the verdict of the jury be correct, committed a horrible, gruesome crime, the murder of her own sleeping, infant daughter, is not evidence of insanity requiring the submission of that question to the jury.
 It is thoroughly established in the law of this State, by numerous decisions of this Court, that the test of insanity as a defense to a criminal charge is whether the accused, at the time of the alleged act, was laboring under such a defect of reason, from disease or deficiency of the mind, as to be incapable of knowing the nature and quality of the act, or, if he does know this, was, by reason of such defect of reason, incapable of distinguishing between right and wrong in relation to such act. State v. Cooper, 286 N.C. 549, 569, 213 S.E. 2d 305 (1975); State v. Humphrey, 283 N.C. 570, 196 S.E. 2d 516 (1973); State v. Johnson, 256 N.C. 449, 452, 124 S.E. 2d 126 (1962); State v. Swink, 229 N.C. 123, 47 S.E. 2d 852 (1948). There is no evidence whatever in this record that the defendant was, at the time her child was shot, laboring under any disease or deficiency of the mind, or defect of reason, or that she did not comprehend the nature and quality of her act, or that she was incapable of distinguishing between right and wrong in relation thereto.
*426As Justice Ervin, speaking for this Court, said in State v. Swink, supra, “Since soundness of mind is the natural and normal condition of men, everyone is presumed to be sane until the contrary is made to appear.” In the absence of any evidence whatever tending to rebut this presumption, it is not required of the State that it offer evidence to establish the defendant’s sanity and it is not. incumbent upon the trial judge to instruct the jury with reference to this matter.
“G.S. 1-180 requires only that the trial judge declare and explain the law ‘arising on the evidence' with respect to all substantial features of the case.” State v. Brower, 289 N.C. 644, 657, 224 S.E. 2d 551 (1976). (Emphasis added.) “The judge is not required to instruct the jury, except on the law of the case.” State v. McKeithan, 203 N.C. 494, 166 S.E. 336 (1932). “The chief purposes of the charge are clarification of the issues, elimination of extraneous matters, and declaration and application of the law arising upon the evidence.” State v. Jackson, 228 N.C. 656, 46 S.E. 2d 858 (1948). (Emphasis added.) With special reference to the matter of insanity, Justice Bobbitt, later Chief Justice, speaking for this Court in State v. Mercer, 275 N.C. 108, 114, 165 S.E. 2d 328 (1968), overruled on other grounds in State v. Caddell, 287 N.C. 266, 215 S.E. 2d 348 (1975), said, “It is, however, error to instruct the jury as to legal principles unrelated to the factual situation under consideration.” In Childress v. Motor Lines, 235 N.C. 522, 530, 70 S.E. 2d 558 (1952), Justice Johnson, speaking for the Court, said, “[I]t is an established rule of trial procedure with us that an abstract proposition of law not pointing to the facts of the case at hand and not pertinent thereto should not be given to the jury.”
 In Patterson v. New York, 97 S.Ct. 2319, 53 L.Ed. 2d 281 (1977), the. Supreme Court of the United States held a New York statute “burdening the defendant in a New York State murder trial with proving the affirmative defense of extreme emotional disturbance as .defined by New York law” does not violate the Due Process Clause of the Fourteenth Amendment of the Constitution of the United States. It necessarily follows that such provision of the United States Constitution is not violated by our rule that, in the absence of any evidence of insanity, it is not error for the trial judge to refuse the defendant’s request that he instruct the jury upon the law relating to insanity as a defense to the charge of murder.
*427  The defendant’s third contention on appeal is that she is entitled to a new trial because the trial court permitted a police officer, called as a witness for the State, to testify concerning a statement made by the defendant to her father in a conversation between them in the interview room at the sheriff’s office, which conversation, unknown to the defendant and her father, was observed and heard by the witness, then in another room, through a one-way glass giving him a view of the interrogation room and the opportunity to hear what was said therein.
After the defendant had been formally arrested and charged with the murder and had orally confessed to the investigating officers that she shot and killed her daughter, the officers left her alone in the interrogation room and then permitted her father to join her there. The only reference in the entire record to this conversation is the following:
“Q. On the date she was charged and after she had been served with a warrant [immediately following which she made her confession to the investigating officers], did you have occasion to observe the defendant and her father, Mr. Matthews, together?
A. Yes, sir, I did.
Q. And where were they at that time?
A. They were in the interview room in the sheriff’s office.
Q. And where were you?
A. I was in a view room which is located next to it.
Q. There is a one-way glass in between, is there not?
A. Yes sir, there is.
Q. Could you see both of them and hear both of them?
A. Yes sir, I could.
Q. Did they have any conversation?
A. Yes sir, they did.
Q. Was anyone else present in the room with them?
*428Q. Would you describe that conversation?
A. I did not write down the conversation. It went something to the effect — Kathy was crying—
Mr. CHESHIRE [defendant’s counsel]: Objection to something to the effect. (Emphasis added.)
EXCEPTION NO. 9
A. Kathy was crying. Her father entered the room and her father said something to the effect, Kathy, you did it, didn’t you? Possibly not the right word but something to that effect. (Emphasis added.)
Mr. CHESHIRE: Objection and move to strike.
Q. What was her response?
COURT: Objection overruled. Motion denied.
EXCEPTION NO. 10
Q. What was her response, if any?
A. Her response was that she did.
Mr. CHESHIRE: Objection and move to strike.
EXCEPTION NO. 11
Q. Did the conversation continue?
A. Yes sir. Her father said to her, asked her why. She said she didn’t know. Her father told her that if she did not want the child, that she knew that the child had a home; that she could have carried the child to their house.
Q. Now, none of these questions or answers in this conversation you have just described were in response to any questions by any law enforcement officer, were they?
A. There were none present in the room.
Q. All right, sir. And there were no questions by law enforcement officers which invoked them that you saw?
*429It is apparent from the record that the ground for the defendant’s objections to this evidence was that the witness was testifying “to the effect” of the conversation rather than to its precise words. It is well settled that “evidence admitted without objection, though it should have been excluded had proper objection been made, is entitled to be considered for whatever probative value it may have,” and the judge is not required to exclude it. Stansbury, North Carolina Evidence (Brandis Rev.), § 27. It is equally well settled that, “although a general objection to obnoxious evidence will be sustained when no ground has been assigned, if upon any ground it ought to have been rejected, yet when the ground of the objection can be fairly inferred from the record as understood by the parties at the time, another cannot be assigned in the reviewing court.” State v. Cumber, 280 N.C. 127, 131, 185 S.E. 2d 141 (1971); Pratt v. Bishop, 257 N.C. 486, 126 S.E. 2d 597 (1962); State v. Wilkerson, 103 N.C. 337, 9 S.E. 415 (1889); Gidney v. Moore, 86 N.C. 484 (1882); Vredenburgh Saw Mill Co. v. Black, 251 Ala. 302, 37 So. 2d 212 (1948); Spencer v. Burns, 413 Ill. 240, 108 N.E. 2d 413 (1952); Monroe Loan Society v. Owen, 142 Me. 69, 46 A. 2d 410 (1946); Kroger Grocery & Baking Co. v. Harpole, 175 Miss. 227, 166 So. 335 (1936); Strong, N.C. Index 2d, Trial, § 15; Stansbury, North Carolina Evidence (Brandis Rev.), § 27; 1 Wigmore on Evidence (3d Ed.), § 18, p. 339; 75 Am. Jur. 2d, Trial, § 167; 88 C.J.S., Trial, § 125b. The stated ground for the objection by the defendant to this testimony was not valid and, considering the objection on that ground alone, there was no error in overruling it.
Furthermore, the admission of this evidence was harmless, beyond a reasonable doubt, in view of the fact that the evidence of the defendant’s much more detailed confession to the police officers, made immediately prior to the conversation here in question, was properly admitted and, in addition, the defendant’s lover, David Stephenson, testified as follows:
“After the warrant was served on her Thursday, March 4th, I talked to her with no officers present. I walked in and Kathy was crying and she grabbed me and I held onto her and we just held each other and I said, ‘Why, Kathy? Why?’ I said, ‘Was it because of me?’ And she stated, ‘David, I don’t want to hurt you no more,’ and paused and I said, ‘Why?’ She *430said, ‘Because I didn’t want to see Tonia hurt like I am hurt.’ ”
Nothing in the record indicates that the conversation between the defendant and Stephenson was induced or monitored, or otherwise overheard by any police officer.
In view of these two properly admitted confessions, it is inconceivable that the verdict of the jury would have been otherwise had the evidence of the conversation between the defendant and her father not been introduced. Thus, even if a proper ground for objection had been stated by the defendant, we conclude that the admission of this evidence was harmless beyond a reasonable doubt and the defendant is not entitled to a new trial on that account. State v. Knight, 282 N.C. 220, 192 S.E. 2d 283 (1972); State v. Cox, 281 N.C. 275, 188 S.E. 2d 356 (1972); State v. Hudson, 281 N.C. 100, 187 S.E. 2d 756 (1972), cert. den., 414 U.S. 1160, 94 S.Ct. 920, 39 L.Ed. 2d 112; State v. Brinson, 277 N.C. 286, 177 S.E. 2d 398 (1970).
We are not to be understood as condoning this unfair tactic of the investigating officers. Although the. defendant had already been arrested and charged with the murder of her child and, thereafter, had confessed to the investigating officers that she was the person who shot and killed the child, when the officers, thereupon, ostensibly withdrew and sent the defendant’s father into the room, the defendant had a “reasonable expectation of privacy” throughout her conversation with her father. See: United States v. Dionisio, 410 U.S. 1, 93 S.Ct. 764, 35 L.Ed. 2d 67 (1973); Terry v. Ohio, 392 U.S. 1, 88 S.Ct. 1868, 20 L.Ed. 2d 889 (1968); Katz v. United States, 389 U.S. 347, 88 S.Ct. 507, 19 L.Ed. 2d 576 (1967). The State was ill-advised in introducing this unfairly obtained evidence so totally unnecessary to the conviction of the defendant. However, since it was so clearly an unnecessary, and so harmless, addition to properly admitted evidence of her confessions and since the defendant’s objection to its introduction was not made upon the ground that the evidence was unconstitutionally obtained, the ruling of the trial court is not basis for granting the defendant a new trial.
The defendant’s other assignments of error set forth in her statement of her case on appeal not having been brought forward into her brief and no argument or authority in support thereof be*431ing set forth therein are deemed abandoned. Rule 28(a) of the Rules of Appellate Procedure, 287 N.C. 741. Nevertheless, in view of the serious nature of this alleged offense, we have carefully reviewed the entire record, including the abandoned assignments of error, and find therein no error which would entitle the defendant to a new trial. The defendant was represented at her trial by able and diligent counsel, employed by her, which counsel was then appointed by the trial court to represent her on appeal, she being then found indigent. She has received able, diligent and vigorous representation, both in the trial court and in this Court. She was found guilty of the murder of her child by a jury, eleven members of which were women. She has had a fair trial, free from prejudicial error.