Following their joint trial, appellants Brandon Bryant, Josiah Hale, and Quincy Wade appeal their convictions for felony murder and attempted armed robbery. ^[1] Having reviewed the record, we con-[*267] elude that the verdict is sufficiently supported by the evidence, and that the trial court did not err in denying appellants’ motions to sever their trials from that of their co-defendants. We also conclude that the trial court did not err in either its evidentiary rulings, or its rulings on challenges raised during voir dire. Therefore, we affirm.

Late in the evening of April 18,1995, appellant Bryant drove his car to a Bartow County convenience store managed by the murder victim, Shirley Hayes. Riding in the car with Bryant were appellants Hale and Wade, and Shawndray Carson. ^[2] Bryant positioned his car so that it was facing away from the building. While Bryant remained in the vehicle, the other three men went inside the store. Carson shot Hayes in the head. Appellants Hale and Wade attempted to remove money from the cash register, but were unsuccessful because they could not open the register drawer. Appellants then left the store and drove off.

At that same time, Robert McCombs and his daughter were driving past the convenience store. They witnessed the three men run from the store, get into a vehicle, and drive off quickly with the vehicle’s lights off. One of the men was carrying a rifle when he exited the store. The McCombses followed the vehicle long enough to obtain its license plate number; they stopped their pursuit when they were fired upon by someone in the fleeing car. The McCombses then returned to the convenience store, where they found Hayes on the floor behind the counter, badly wounded but still alive.

Hayes was hospitalized from April 18, 1995 until June 1, 1995. During her hospital stay, she underwent two surgeries, remained in intensive care for several weeks, was on a ventilator for approximately two weeks, and contracted pneumonia. Hayes also was treated with medication to prevent blood clotting that could result from the prolonged immobility required for her recuperation. After her release from the hospital, Hayes was placed on a physical therapy regimen, and used a walker and wheelchair to move about. On June 25, 1995, Hayes died of a pulmonary embolism while at her home. Evidence introduced at trial showed that the pulmonary embolism resulted when a blood clot that originated in her leg became dislodged and traveled to her pulmonary artery, blocking the transfer of blood to the heart.

After their arrests, each appellant gave an in-custody interview in which he stated his level of involvement in the attempted robbery and the shooting of Hayes. Sonja Hicks, an acquaintance of appellants, testified at trial that, prior to the appellants’ arrests and while[*268] in appellant Wade’s presence, appellant Bryant told her that while he sat in the car, the others went into the convenience store, where Carson shot Hayes while Wade and Hale attempted unsuccessfully to open the cash register.

1. The evidence discussed above was sufficient to enable a rational trier of fact to conclude beyond a reasonable doubt that appellants are guilty of felony murder and attempted armed robbery. ^[3]

(a) Appellants urge that Hayes possessed certain risk factors not directly related to her gunshot wounds that may have contributed to her suffering a pulmonary embolism. In making this argument, appellants point to medical evidence introduced at trial that risk factors for pulmonary embolism include obesity, use of estrogen, and cancer, and that Hayes was slightly obese, used estrogen, and had previously been treated for cancer. However, we note that additional medical evidence introduced at trial showed that the most common risk factor for pulmonary embolism is prolonged immobility, such as that experienced by Hayes during her recovery from appellants’ attack. At trial, Hayes’s physician testified that her obesity was not, in and of itself, a risk factor; rather, it only became a risk factor to the extent that she was immobilized by it. The evidence indicated that despite being obese, Hayes was active in her lifetime, and did not become immobile until she was wounded during appellants’ attack. Following that attack, Hayes underwent a long period of recuperation that required a great deal of immobility. Furthermore, Hayes’s physician testified that her previous cancer could not have contributed to her pulmonary embolism, because she had no malignancy at the time of her death. Additional testimony showed that her dosage of estrogen was too low to have put her at risk for pulmonary embolism. Hayes’s treating pulmonologist testified that the facts discussed above led him to conclude that, before being injured in appellants’ attack, her risk of suffering a pulmonary embolism was “extremely remote.”

Based upon this evidence, a rational jury could conclude that even though Hayes had previously suffered from some conditions that might have put her at risk for pulmonary embolism, the injuries she sustained in appellants’ attack on her either (1) “directly and materially contributed to the happening of a subsequent accruing immediate cause [of death],” or (2) “materially accelerated the death, although [it was] proximately occasioned by a pre-existing cause.” ^[4] In either event, the evidence was sufficient to authorize the jury’s guilty[*269] verdicts.

(b) Appellant Bryant, the driver of the car who remained outside of the convenience store during the attempted robbery, claims that he did not know that his co-defendants intended to commit armed robbery. He claims that the State merely proved his presence at the scene of the crime, an insufficient basis upon which to affirm his convictions. ^[5] However, the evidence showed that, in his custodial interview, Bryant admitted that he knew the others were armed and were going inside the store to rob it. The evidence also showed that, prior to arriving at the convenience store, appellants discussed and planned their robbery, and actually searched out the best store to rob. Further, McCombs testified that, as the other three appellants exited the store, Bryant’s car was positioned facing away from the door and toward the adjacent roadway. Thus, Bryant had backed his car in, suggesting that he had positioned it for a fast getaway after the robbery. Thus, the evidence showed much more than Bryant’s mere presence at the scene of the crime, and based upon that evidence, the jury was authorized to conclude that Bryant aided and abetted his co-defendants in attempting to commit the armed robbery which lead to Hayes’s murder.

2. The trial court did not abuse its discretion in denying Bryant’s and Hale’s motions to sever their trials from that of their co-defendants. In deciding a motion to sever, a trial court must consider (1) whether a joint trial will create confusion regarding evidence or law; (2) whether there is danger that evidence implicating one defendant will be considered against co-defendants, despite limiting instructions; and (3) whether the co-defendants will press defenses that are ántagonistic to one another. ^[6] Regarding the first prong, Bryant and Hale do not attempt to explain on appeal how their joint trial created confusion of evidence or law.

Regarding the second prong, it is urged that the introduction of appellants’ custodial statements detailing their respective degrees of involvement in the crime was harmful because the statements implicated the declarants’ co-defendants. However, each co-defendant’s custodial statement was extensively redacted prior to its introduction, in accordance with Bruton v. United States. 7 When the appellants’ státements were introduced, the trial court clearly instructed the jury that each statement was admissible only against the declarant, and did not impact upon the adjudication of the other co-defendants’ guilt or innocence. After the admission of all the custo[*270] dial statements, the trial court again gave the jury this limiting instruction. Having reviewed the record, we conclude that the trial court’s prophylactic measures adequately guarded against the danger that appellants’ incriminating custodial statements might be considered against non-declarant co-defendants. ^[8]

Finally, regarding the third prong of this analysis, Bryant and Hale do not explain on appeal how their defenses were antagonistic to each other. It would appear that the joint trial did not impact them in this regard, since none of the co-defendants presented any evidence at trial. Accordingly, for the reasons discussed above, we conclude that the trial court did not abuse its discretion in denying the motions to sever.

3. Appellant Wade urges that the trial court erred by admitting Hayes’s death certificate into evidence, because its statements concerning the cause of Hayes’s death were inadmissible hearsay. A review of the transcript, however, shows that Wade did not raise this objection at trial, and it cannot be raised for the first time on appeal. ^[9]

Appellant Wade also urges that the trial court erred by permitting the jury to view a redacted version of the death certificate during deliberations, because it served as a “ ‘continuing witness’ ” concerning the cause of Hayes’s death. The only portion of the certificate that the trial court allowed to be viewed during deliberations concerned the death itself, and the immediate causes of the death; the portion detailing that Hayes’s injuries were sustained in an attempted armed robbery was properly redacted when the certificate was tendered into evidence. ^[10]

The “ ‘continuing witness’ ” rule prohibits writings from going out with the jury when the evidentiary value of such writings depends “ ‘on the credibility of the maker.’ ” ^[11] Documents that are prohibited by the “ ‘continuing witness rule’ ” from going out with the[*271] jury include answers to written interrogatories, ^[12] written dying declarations, ^[13] and signed statements of guilt. ^[14] These documents, which generally contain their makers’ assertions of purported truths, ^[15] are ascribed evidentiary value only to the extent that their makers are credible. However, unlike these examples, a death certificate properly completed by a medical examiner is considered prima facie evidence of both the death itself and the cause of the death. ^[16] The prima facie evidentiary value ascribed to a death certificate’s representation of a death and its causes is not dependent upon the medical examiner’s credibility. In fact, a death certificate is accorded initial prima facie evidentiary value regardless of the examiner’s credibility. ^[17] For this reason, we conclude that death certificates that are properly redacted to show only prima facie evidence of the fact that a death occurred and the causes of the death are not subject to the “ ‘continuing witness rule.’ ”

4. The trial court did not err in denying appellant Bryant’s two challenges for cause raised during voir dire. One of the challenges was directed at a juror who, Bryant alleges, stated during voir dire that she is the mother-in-law of a GBI agent who investigated Hayes’s murder. While there is no evidence of record to support Bryant’s contention, ^[18] we nonetheless conclude that even if the contention is true, the trial court did not err in denying the challenge for cause. As stated in OCGA § 15-12-163 (b) (4), a juror need only be struck for cause when he or she is in a close relationship to the prosecutor of a criminal trial, or the accused, or the victim. Here, if Bryant’s allegations are true, the GBI agent was not a prosecutor, but rather merely an officer of the State assigned to investigate the crime for which appellant was being tried. As such, the GBI agent was a potential witness at trial. However, it is established that a potential[*272] juror need not be automatically dismissed for cause on that basis. ^[19]

For these same reasons, we conclude that the trial court did not err in refusing to dismiss for cause a second juror who, several years before trial, was divorced from the lead criminal investigator assigned to this case. Moreover, we note that in response to appellant’s challenge for cause, the trial court stated on the record that during voir dire, the juror clearly stated her ability to serve fairly and impartially on the jury. Hence, it was not error to deny appellant’s attempted strikes. ^[20]

Judgment affirmed.