We review Ira Amazon’s convictions and sentences to death for the murders of a mother and daughter. Jurisdiction is mandatory pursuant to article V, section 3(b)(1), Florida Constitution. We affirm the convictions, but vacate the sentences and remand with directions.
Neighbors found Joy Chapin and her eleven-year-old daughter, Jennifer, dying from multiple stab wounds in their Pinellas County home early in the morning of December 1, 1981. A neighbor had been alerted when she received a telephone call from Jennifer, interrupted by screams. Jennifer was found lying next to the telephone, her mother was found downstairs.
Amazon, who lived next door to the Cha-pins, was among the crowd watching the subsequent police investigation. He concocted a burglary of his own home, either before or after the murders, and went to police with an exculpatory story, i.e. there had been two homes entered that night. Twelve hours later, he was arrested after his fingerprints were matched to those found on a window screen pried off the Chapin’s window to gain entry. Other circumstantial evidence also linked him to the murders. At first denying the crimes, Amazon eventually confessed to detectives.
A grand jury indicted Amazon on two counts of first-degree murder. The same day as the indictments, the state filed an information charging burglary and sexual battery. Before trial, Amazon pleaded guilty to the burglary and sexual battery charges then moved to dismiss the murder charges on double jeopardy grounds. The trial judge denied the motion, and the district court declined to review the order, without prejudice to raise the issue on appeal. Amazon was convicted of first-degree murder on both counts. The jury recommended life sentences, but the trial judge overrode the recommendation and sentenced Amazon to death.
DOUBLE JEOPARDY
Amazon first challenges his prosecution for felony murder after he was subjected to jeopardy for the underlying crimes of burglary and sexual battery. The prosecution proceeded under both premeditated and felony first degree murder theories, and the jury was instructed accordingly. The verdict form did not specify upon which theory the jury based its finding of guilt.
Amazon’s double jeopardy claim fails. In State v. Enmund, 476 So.2d 165 (Fla.1985), we held that a felony underlying a felony murder charge is not the “same offense” for purposes of double jeopardy, and therefore a separate conviction and sentence may be had for the underlying felony. Serial prosecutions are permissible for crimes which are not the “same offense” under the rule of Blockburger v. United States, 284 U.S. 299, 52 S.Ct. 180, 76 L.Ed. 306 (1932). In Illinois v. Vitale, 447 U.S. 410, 100 S.Ct. 2260, 65 L.Ed.2d 228 (1980), the Supreme Court held that a prior conviction for failure to reduce speed to avoid collision did not bar, on double jeopardy grounds, a subsequent prosecution for manslaughter arising from the same criminal episode. The Court held that this was so, even though the prosecution for manslaughter might entail proof of all the elements of failure to reduce speed to avoid collision, so long as the lesser offense was not the “same” under Blockburger. The Court distinguished the case from Brown v. Ohio, 432 U.S. 161, 97 S.Ct. 2221, 53 L.Ed.2d 187 (1977), wherein conviction for a prior lesser offense which was the “same” under Blockburger barred a subsequent prosecution on the greater offense.
In the case sub judice, the underlying felonies are not the “same” under Blockburger, and the state would not be barred from serial prosecutions of the underlying felonies and the felony murders. If serial prosecution is permitted, which raises more serious double jeopardy considerations than here, then there is no double jeopardy bar to accepting the guilty pleas to the underlying felonies and withholding adjudication and sentencing until the felony murder charges have been resolved, as was done here.
AMAZON’S ABSENCE FROM THE JURY VIEW
Amazon next challenges his absence from the jury view of the crime scene. He argues that he was unaware that testimony would be presented during the view (explanations by investigators of what they found and where they found it), and that it was fundamental error for the trial court to accept the waiver by his attorneys rather than to conduct a hearing to determine whether Amazon knowingly and voluntarily waived his presence. Following oral argument before this Court, we relinquished jurisdiction of the case for an evi-dentiary hearing on the circumstances surrounding the waiver. The trial judge concluded that Amazon “knowingly and intelligently” waived his presence.
A capital defendant is free to waive his presence at a crucial stage of the trial. Peede v. State, 474 So.2d 808 (Fla.1985). Waiver must be knowing, intelligent, and voluntary. Francis v. State, 413 So.2d 1175 (Fla.1982). Counsel may make the waiver on behalf of a client, provided that the client, subsequent to the waiver, ratifies the waiver either by examination by the trial judge, or by acquiescence to the waiver with actual or constructive knowledge of the waiver. See State v. Melendez, 244 So.2d 137 (Fla.1971). Here, trial counsel clearly waived Amazon’s presence knowingly, intelligently and voluntarily. Amazon knew of the waiver, because he had been consulted by his attorneys on the point and advised to waive his presence. He authorized his attorneys to make the waiver. His authorization was knowing and intelligent and as voluntary as any decision made by a client who relies upon and accepts advice of counsel. Amazon subsequently acquiesced to the waiver, with actual notice, and now cannot be heard to complain.
JUROR CONDUCT
Amazon next urges that certain conduct of the jurors requires reversal. After the trial was finished, the trial judge learned of violations of the sequestration rules and conducted a special hearing. Amazon urges that the burden is on the state to refute a presumption of prejudice raised whenever juror misconduct is shown. However, that is not the rule in Florida, as one of the cases cited by Amazon explains:
If the [misconduct is] such that [it] would probably influence the jury, and the evidence in the cause is conflicting, the onus is not on the accused to show he was prejudiced for the law presumes he was. But it should be clearly understood that not all [misconduct] will vitiate a verdict, even though such conduct may be improper. It is necessary either to show that prejudice resulted or that the [misconduct was] of such character as to raise a presumption of prejudice.
Russ v. State, 95 So.2d 594, 600-01 (Fla.1957). The United States Supreme Court has said:
In a criminal case, any private communication, contact, or tampering directly or indirectly, with a juror during a trial about the matter pending before the jury is, for obvious reasons, deemed presumptively prejudicial.... The presumption is not conclusive, but the burden rests heavily upon the Government to establish, after notice to and hearing of the defendant, that such contact with the juror was harmless to the defendant.
Remmer v. United States, 347 U.S. 227, 229, 74 S.Ct. 450, 451, 98 L.Ed. 654 (1954). In other words, potentially harmful misconduct is presumptively prejudicial, but the defendant has the initial burden of establishing a prima facie case that the conduct is potentially prejudicial.
The record in this case shows that three jurors went to the bar in the motel where the jury was sequestered on the evening after the guilty verdicts but before the sentencing phase of the trial. Clearly no prejudice could have resulted since the jury recommended life. One of the same jurors was seen in the bar one evening during the guilt phase of the trial. The record fails to show a prima facie case that any potentially prejudicial communication occurred during this visit. Another of the same jurors, an alternate, had dinner at the motel with his fiance, but the case was not discussed. Again, no prima facie potential prejudice is shown.
A fourth juror testified he watched news accounts of the trial on television, with the sound turned off. His roommate, the alternate juror discussed above, also saw the television screen. One of the news accounts included videotape of the testimony of an important state witness, causing the fourth juror to comment to the alternate that the witness’s testimony had been “impressive.” While this establishes a prima facie case of potential prejudice, the presumption is rebutted by the nature of the occurrence: the sound was off, so the jurors were not exposed to prejudicial verbiage, and the brief footage of the witness, which merely reprised what the jury had seen for itself that day, cannot conceivably have influenced the result. The witness was a metallurgist whose testimony tended to show that Amazon took a knife into the house with him, buttressing the state’s case that the murders were premeditated. However, Amazon’s defense was that the murders were second-degree, “depraved mind” killings. The question of whether Amazon took a knife with him or grabbed one from a counter inside the Cha-pin home, as he testified, is not dispositive of his state of mind at the moment of the killings. Likewise, the metallurgist’s testimony was not dispositive of the question of whether Amazon took the knife into the Chapin home. The connection between the metallurgist’s testimony and the question of first or second-degree murder is simply too remote to conclude that a brief visual reprise of the witness testifying could have had a substantial impact on the outcome. Finally, the juror’s “impressive” comment does not show that the juror had developed a premature opinion about the case. Jordan v. State, 22 Fla. 528 (1886).
REMAINING ISSUES IN GUILT PHASE
We find no merit in the remaining issues raised regarding the guilt phase of the trial. Amazon claims error in admitting testimony about a burglary from a neighbor’s home some time before the murders. The murder weapon matched the description of a knife taken in the burglary, and evidence showed that Amazon had given his mother a set of knives matching the description of the stolen set shortly after the burglary. The evidence therefore tended to show Amazon had access to the murder weapon and carried it with him into the Chapin home, relevant to the question of premeditation. Amazon's claim that this was impermissible evidence of a collateral crime is groundless. Ruffin v. State, 397 So.2d 277 (Fla.), cert. denied, 454 U.S. 882, 102 S.Ct. 368, 70 L.Ed.2d 194 (1981); Ashley v. State, 265 So.2d 685 (Fla.1972).
Likewise, Amazon’s objection to the metallurgist’s testimony regarding marks on a screen removed to gain entry into the Chapin home is meritless. Although the expert could not conclusively say the marks were made with the murder weapon, which would tend to prove that the killer took the knife into the home, he did testify that there was a high probability that the murder weapon made the marks, based on his expert knowledge. The testimony was probative evidence requiring specialized knowledge, and it was not error to admit the testimony over the argument that the lack of conclusiveness meant the jury was just as qualified as the expert to draw the conclusion from the physical evidence.
SENTENCE
Amazon raises several arguments attacking the sentencing phase, but we need only address one: the trial judge’s override of the jury’s recommendation of life. “In order to sustain a sentence of death following a jury recommendation of life, the facts suggesting a sentence of death should be so clear and convincing that virtually no reasonable person could differ.” Tedder v. State, 322 So.2d 908, 910 (Fla.1975). The trial judge found four aggravating circumstances: the murder was committed during a rape, burglary, kidnapping—the court reasoned that Amazon forced Mrs. Chapin to move after the rape to show him where he could find valuables, constituting asportation sufficient to support a finding of kidnapping; the murders were committed to avoid arrest—a detective testified that Amazon said he killed the victims because they could identify him; the murders were committed for pecuniary gain—Amazon admitted he demanded valuables after the rape; the murders were especially heinous, atrocious, and cruel — the circumstances of the killings and the 15-20 minutes it took the victims to bleed to death from multiple stab wounds was found to support this aggravating factor.
The trial judge found no mitigating factors. However, we are persuaded that the jury could have properly found and weighed mitigating factors and reached a valid recommendation of life imprisonment. We believe there was sufficient evidence for the jury to have found that Amazon acted under extreme mental or emotional disturbance. The defense theory in the guilt phase was that Amazon had acted from a “depraved mind,” i.e. committed second-degree murder. There was some inconclusive evidence that Amazon had taken drugs the night of the murders, stronger evidence that Amazon had a history of drug abuse, and testimony from a psychologist indicated Amazon was an “emotional cripple” who had been brought up in a negative family setting and had the emotional maturity of a thirteen-year-old with some emotional development at the level of a one-year-old. Age could also be found as a mitigating factor. Although Amazon was nineteen, an age which we have held is not per se a mitigating factor. Peek v. State, 395 So.2d 492 (Fla.1980), cert. denied, 451 U.S. 964, 101 S.Ct. 2036, 68 L.Ed.2d 342 (1981), the expert testimony about Amazon’s emotional maturity suggests that the jury could have properly found age a mitigating factor in this case.
In light of these mitigating circumstances, one may see how the aggravating circumstances carry less weight and could be outweighed by the mitigating factors. The heinous, atrocious and cruel murders were committed in an irrational frenzy. The evidence that Amazon killed to avoid arrest is the unsupported assertion by a detective that Amazon told him this. The defense showed on cross-examination that this statement was not recorded anywhere by the detective, and the jury could well have discounted the evidence. While the fact that the victims knew Amazon could allow inference of the aggravating factor, when considered in light of the “frenzied attack” hypothesis, Amazon may well have not considered avoidance of arrest when he killed his victim.
In other words, the jury could have found the crimes sufficiently serious to warrant first-degree murder convictions, but the combination of the “depraved mind” defense and the possible mitigating factors discussed supra mitigated against a recommendation of death. The facts are not so clear and convincing that no reasonable person could differ that death was the appropriate penalty.
Accordingly, we affirm the judgment of guilt, but vacate the sentences of death with directions that appellant be sentenced to life imprisonment pursuant to section 775.082, Florida Statutes (1981), for each murder. The sentencing court shall have the discretion to decide whether the two sentences of life imprisonment are to be served concurrently or consecutively.
It is so ordered.
oveeton, McDonald, ehrlich and SHAW, JJ., concur.
BOYD, C.J., concurs in part and dissents in part with an opinion, in which ADKINS, J., concurs.
. When a waiver is required of the defendant as to any aspect or proceeding of the trial, experience clearly teaches that it is the better procedure for the trial court to make inquiry of the defendant and to have such waiver appear of record. The matter would thus be laid to rest.