*400As pertinent here, the statute punishing "open and gross lewdness and lascivious behavior," G. L. c. 272, § 16, has remained unchanged for more than 230 years. See Commonwealth v. Quinn, 439 Mass. 492, 495 & n.7, 789 N.E.2d 138 (2003), citing St. 1784, c. 40, § 3. However, during that time, the definition of the crime has "evolved through our decisional law." Commonwealth v. Maguire, 476 Mass. 156, 158, 65 N.E.3d 1160 (2017). The Maguire decision represents the most recent "judicial construction" of the statute. Id. at 161, 65 N.E.3d 1160, quoting from Commonwealth v. Ora, 451 Mass. 125, 128, 883 N.E.2d 1217 (2008). In Maguire, the court announced *269that one of the five elements of the offense (element four) requires the Commonwealth to prove an "objective component," namely, that the defendant's conduct not only caused one or more persons to be shocked or alarmed, but in addition, "that 'shock' or 'alarm' was an objectively reasonable reaction in the circumstances of the conduct." Maguire, supra at 161, 65 N.E.3d 1160.1 This requirement does not appear in any previously reported Massachusetts appellate decision. Not surprisingly, the jury in this case were not instructed in accordance with Maguire, which was decided approximately three months after the conclusion of the defendant's trial. We conclude that the absence of such an instruction created a substantial risk of a miscarriage of justice, and accordingly reverse the defendant's conviction of open and gross lewdness.
Background. Taking the evidence in the light most favorable to the *401Commonwealth, Commonwealth v. Latimore, 378 Mass. 671, 676-677, 393 N.E.2d 370 (1979), the jury could have found the following facts.
On August 9, 2015, a twenty-seven year old female witness, N.M., was out for a boat ride on the Charles River with her father and some friends. The boat was tied up in front of the Hatch Shell on the Esplanade, which is owned by the Department of Conservation and Recreation, patrolled by the State police, and open to the public. N.M. noticed two children, between the ages of five and seven, who were riding scooters. They stopped suddenly and turned their heads toward something. When she followed their gaze to see what had caught their attention, she saw an individual, later identified as the defendant, walking in a "casual strut" down the walkway on the Esplanade. He walked the way models walk down the runway, to "let everybody see the outfit." The defendant was wearing a black sock-like object over his genitals, held in place by three strings in the shape of a "T." N.M. described it as a "banana hammock." The defendant's buttocks were exposed and he was otherwise completely naked.
When N.M. saw the defendant, she felt "shocked" and "just a little disgusted." She explained that she "wouldn't expose that to anybody," and further described what she had seen as "just a little unnerving." She testified that her reaction was based, in part, on the fact that there were children in the area who also saw the defendant. She took a photograph of the defendant, which was admitted in evidence. N.M. then decided to flag down a State police trooper passing by to report what she had seen. As the trooper, David Twomey, approached the defendant, he quickly turned away and put on his pants. The defendant *270appeared nervous, as "his eyebrows were twitching and he was stuttering." He told Twomey that he was sunbathing. Twomey subsequently placed the defendant under arrest.
Discussion. 1. Sufficiency of the evidence. The defendant argues on appeal that the Commonwealth's evidence was not sufficient to prove that his behavior was objectively and subjectively shocking or alarming as required by Maguire.2
Initially, we must determine whether the interpretation of the open and gross *402lewdness statute announced in Maguire is applicable to the case before us. "Where a decision does not announce new common-law rules or rights but rather construes a statute, no analysis of retroactive or prospective effect is required because at issue is the meaning of the statute since its enactment." McIntire, petitioner, 458 Mass. 257, 261, 936 N.E.2d 424 (2010). See id. at 262 n.7, 936 N.E.2d 424. Maguire is applicable in the instant case because the court, through the process of judicial construction, explained that the open and gross lewdness statute contains an objective component.
The question for us thus becomes "whether, after viewing the evidence in the light most favorable to the prosecution, any rational trier of fact could have found the essential elements of the crime beyond a reasonable doubt" (emphasis omitted). Latimore, 378 Mass. at 677, 393 N.E.2d 370. "The inferences drawn from [the] evidence need only be reasonable and possible, not necessary or inescapable." Commonwealth v. Morgan, 449 Mass. 343, 349, 868 N.E.2d 99 (2007) (quotation omitted). See Commonwealth v. Bush, 427 Mass. 26, 30, 691 N.E.2d 218 (1998).
a. Objective component of "shock" or "alarm." The fourth element of the crime of open and gross lewdness, as defined anew in Maguire, requires the Commonwealth to "demonstrate that 'shock' or 'alarm' was an objectively reasonable reaction in the circumstances of the conduct." Maguire, 476 Mass. at 161, 65 N.E.3d 1160. Whether a person's reaction is reasonable based on the circumstances is typically a question to be determined by the fact finder. See ibid. See also Trenz v. Norwell, 68 Mass. App. Ct. 271, 275, 861 N.E.2d 777 (2007) ("Reasonableness is a question of fact for the [fact finder] whose decision is based on consideration of all the relevant circumstances" [quotation omitted] ).
Although we regard this as a close question, reasonable minds could differ as to whether N.M.'s reaction to the defendant's deliberate exposure of his buttocks in a public area was objectively reasonable.3
*271Thus, the Commonwealth should have the opportunity *403to present its case to a properly instructed jury, at a new trial.
b. Subjective component of "shock" or "alarm." The fifth element of proof requires the Commonwealth to demonstrate that at least one person was in fact shocked or alarmed by the defendant's exposure. See Quinn, 439 Mass. at 501, 789 N.E.2d 138 ; Commonwealth v. Botev, 79 Mass. App. Ct. 281, 287-288, 945 N.E.2d 956 (2011). "Where an 'observer suffered significant negative emotions as a result of the exposure,' the observer's reaction 'could justifiably be deemed alarm or shock,' ... [sufficient] to convict a defendant of open and gross lewdness." Commonwealth v. Pereira, 82 Mass. App. Ct. 344, 347, 973 N.E.2d 679 (2012), quoting from Commonwealth v. Kessler, 442 Mass. 770, 775, 817 N.E.2d 711 (2004). "[T]he fact finder may consider not only the words used by the witness, but also other indicia of the witness's emotional state" in determining whether the observer suffered significant negative emotions as a result of the defendant's actions. Pereira, supra. One such indicium is "whether the witness immediately reported the incident." Commonwealth v. Militello, 66 Mass. App. Ct. 325, 334, 848 N.E.2d 406 (2006).
Here, N.M. testified that she was "shocked" and "just a little disgusted" by the defendant's exposure. She found it "[a] little nerve racking" both because she had never seen anything similar before and because there were children around. Indeed, she took a photograph of what she had seen and flagged down Twomey. While N.M. testified that her reaction was based in part on her concern over the impact of the defendant's behavior on the children who were on the Esplanade, she also testified that she experienced "a little shock[ ]" herself. For this reason, there was sufficient evidence to permit the jury to find that the Commonwealth had proved the fifth element of the offense.
2. Testimony and closing argument. The defendant contends that it was error to allow N.M. to testify as to her observations of the children on the Esplanade. Because the defendant did not object to this testimony, we review to determine if there was error, and if so, whether it created a substantial risk of a miscarriage of justice. See Commonwealth v. Renderos, 440 Mass. 422, 425, 799 N.E.2d 97 (2003). Although "[v]icarious concern for other people," without more, is not sufficient to demonstrate an individual's shock or *404alarm, see Maguire, 476 Mass. at 160, 65 N.E.3d 1160, the Commonwealth had the right to present N.M.'s account of the circumstances in which she made her observations. "[T]he prosecution with its burden of persuasion needs evidentiary depth to tell a continuous story." Old Chief v. United States, 519 U.S. 172, 190, 117 S.Ct. 644, 136 L.Ed.2d 574 (1997). See Commonwealth v. Whitehead, 379 Mass. 640, 657, 400 N.E.2d 821 (1980). There was no error, let alone a substantial risk of a miscarriage of justice.4 *2723. Jury instructions. The defendant maintains that the judge omitted an instruction on an essential element of the crime, namely the "objective component" of open and gross lewdness, described for the first time in Maguire, supra, as "the focus of the fourth element." 476 Mass. at 159, 65 N.E.3d 1160.
In this case, the judge instructed the jury that the crime of open and gross lewdness consisted of five elements, as follows:
"First, that the defendant exposed his genitals or buttocks to one or more persons; that the defendant did so intentionally; that-third, that the defendant did so openly, that is, either he intended public exposure or he recklessly disregarded a substantial risk of public exposure to others who might be offended by such conduct; fourth, that the defendant's act was done in such a way as to produce alarm or shock and, fifth that one or more persons were-were, in fact, alarmed or shocked."5
Following the decision in Maguire, the District Court model jury instruction was revised. Element four of the five-element instruction now reads as follows: "Fourth: That the defendant's act was done in such a way as would alarm or shock a reasonable *405person."6
Due to the defendant's failure to object to the jury instructions given at trial, our review is limited to determining whether any error in the instructions gave rise to a substantial risk of a miscarriage of justice. See Commonwealth v. Azar, 435 Mass. 675, 685, 760 N.E.2d 1224 (2002). See also Commonwealth v. Johnston, 467 Mass. 674, 704, 7 N.E.3d 424 (2014) (applying substantial likelihood of miscarriage of justice standard where, although defendant failed to object to jury instructions, he was entitled to "benefit of changes in decisional law ... announced after trial and pending his direct review"). In applying the substantial risk of a miscarriage of justice standard, "[w]e consider the strength of the Commonwealth's case, the nature of the error, the significance of the error in the context of the trial, and the possibility that the absence of an objection was the result of a reasonable tactical decision." Azar, supra at 687, 760 N.E.2d 1224.
An initial question, therefore, is whether the pre- Maguire model instruction effectively communicated to the jury that in order to find the defendant guilty, it was not sufficient for the Commonwealth to prove that his conduct produced shock or alarm in the mind of N.M., but that, as the post- Maguire model instruction states, the Commonwealth also must prove that "the defendant's act was done in such a way as would alarm or shock a reasonable person." Instruction 7.400 of the Model Jury Instructions for Use in the District Court (May, 2017), fourth element. Nowhere in the judge's instructions is there any reference to the distinction between the subjective and the objective components of the crime. The jury were not *273informed that although the victim's experience of shock or alarm may satisfy the fifth element of the offense, the fourth element requires the jury to answer the independent question whether the victim's reaction was objectively reasonable. Finally, it should be noted that after the jury began their deliberations, they asked the court for "a copy of the statute in question including the five conditions to be met." After consulting with counsel, the judge reinstructed the jury using the pre- Maguire model instruction followed by an explanation of the intent element and a reference to the fourth and fifth elements that did not convey the distinction between the subjective and the objective components. For these reasons, we conclude that the instructions in this case were deficient for failing to communicate to the jury that in order to convict the defendant of *406open and gross lewdness they must find that the defendant's conduct produced shock or alarm in two independent respects, namely that N.M. experienced that reaction and that a reasonable person in her position also would have experienced shock or alarm.
Furthermore, the Commonwealth's case was arguably weak as it related to the reasonableness of the victim's shock or alarm. The evidence indicates that N.M., from her vantage point near a boat on a dock on the Charles River located near the Hatch Shell, observed the defendant, from the side, as he walked along the Esplanade wearing only a banana thong. Because his genitals were covered, the judge correctly instructed the jury that the only basis for finding that N.M. suffered shock or alarm at the appearance of the defendant, from the side, was the exposure of his buttocks. Even granting that N.M. was shocked or alarmed as a result of this experience, the jury were not asked and thus did not determine whether a reasonable person in N.M.'s position would have experienced shock or alarm based on the observation of the defendant's buttocks from N.M.'s distant vantage point.
The defendant's failure to object to the jury instruction also cannot be characterized as a reasonable tactical decision. The judge recited the District Court model jury instruction to the jury, and no reported appellate decision prior to Maguire put the defendant on notice that proof that some particular person experienced shock or alarm as a result of witnessing the defendant's intentional act of exposing his buttocks in public is a fact separate and independent from whether a reasonable person in the victim's position would experience shock or alarm. See, e.g., Commonwealth v. Fitta, 391 Mass. 394, 396, 461 N.E.2d 820 (1984) (conviction for open and gross lewdness and lascivious behavior requires that "defendant's act [is] committed in such a way as to produce alarm or shock" [quotation omitted] ).7 This, coupled *274with the Commonwealth's *407arguably weak case as to the objective component of the open and gross lewdness statute, leads us to conclude that the defendant's failure to object to the jury instructions cannot be considered a reasonable tactical decision.
Under these circumstances, we conclude that there was a substantial risk of a miscarriage of justice. See Commonwealth v. Stoltz, 73 Mass. App. Ct. 642, 644, 900 N.E.2d 880 (2009), quoting from Commonwealth v. Hall, 48 Mass. App. Ct. 727, 730, 725 N.E.2d 247 (2000) ("[W]here 'error pertains to the definition given to the jury of the crime charged, the possibility of a substantial risk of a miscarriage of justice is inherent' "). For this reason, the defendant is entitled to a new trial.8
Judgment reversed.
Verdict set aside.