Surveillance footage, cellphone records and forensic evidence helped prosecutors counter Justin Smith’s testimony that Dianna Brice’s shooting was accidental.
PHILADELPHIA, Penn. — The murder case against Justin Smith was built across surveillance cameras, cellphone towers, two vehicles, a burned car and physical evidence recovered after Dianna Brice disappeared. When Smith finally stood trial more than five years later, prosecutors used that trail to challenge his claim that the pregnant 21-year-old had died accidentally during a struggle over a handgun.
A Philadelphia jury rejected Smith’s account and convicted him of first-degree murder in Brice’s death and third-degree murder of the unborn child she was carrying. The verdict also covered the concealment that prosecutors said investigators had reconstructed step by step: arson, conspiracy to commit arson, evidence tampering and abuse of a corpse, along with two firearm offenses. Common Pleas Court Judge Anthony Kyriakakis sentenced the 28-year-old defendant to life without parole and imposed another 40 to 80 years consecutively.
The strength of the prosecution’s case did not depend on a single confession, witness or forensic result. Instead, prosecutors argued that several different kinds of evidence converged on the same timeline. Brice and Smith were together before she vanished. Their phones traveled together. Her phone stopped transmitting. Cameras captured Smith and an accomplice after the disappearance. Blood was later found in a vehicle they used. Smith’s Ford was burned. A cartridge casing recovered from the damaged car was linked to evidence found with Brice. Smith then left Pennsylvania and remained a fugitive for years.
The timeline began March 30, 2021, when Brice was last seen leaving a laundromat in Delaware County with Smith. She was 14 weeks pregnant with his child. Trial testimony showed that the couple had been arguing after Brice learned she had tested positive for herpes and believed Smith had transmitted the infection to her. Prosecutors did not ask jurors to treat the dispute alone as proof of murder. Instead, they used it to establish what was happening immediately before Brice disappeared.
Cellphone records provided the next piece. A former Philadelphia police detective who testified as a cell-site expert said Brice’s and Smith’s devices traveled along the same general path on the day she went missing. At some point, Brice’s phone stopped providing location information. That electronic silence became one marker in the prosecution’s chronology, showing a break between the period when Brice was still moving with Smith and the period when investigators documented his later actions.
Surveillance cameras filled in portions of what came next. Philadelphia Detective Thorsten Lucke testified about footage investigators used to trace Smith’s Ford Fusion and a Hyundai connected to his friend Tylydia Garnett. Cameras recorded activity around a garage in Kensington. Prosecutors said footage showed Garnett carrying trash bags and later showed her and Smith moving what appeared to be a heavy object into the Hyundai.
The Hyundai later produced physical evidence. Investigators found Brice’s blood inside it, prosecutors said. Cameras also helped detectives track movements toward the area of Southwest Philadelphia where Brice’s body was eventually found. Other footage showed events preceding the destruction of Smith’s Ford Fusion, including Garnett obtaining gasoline. The Ford was later found burned near Cobbs Creek.
Fire did not eliminate everything inside the vehicle. According to the Philadelphia District Attorney’s Office, investigators recovered a fired cartridge casing from the burned Ford. Forensic testing matched it to a casing found with Brice. Prosecutors used that result to link the vehicle directly to physical evidence associated with the shooting, undermining any suggestion that the burned car and Brice’s death were separate events.
Brice’s body was discovered April 5, six days after she disappeared. The medical examiner testified that she had been shot 11 times in the head and once in the shoulder. The prosecution treated that evidence as central to its response to Smith’s accident defense. Assistant District Attorney Lauren Crump argued that the location and concentration of the wounds did not fit an account in which a weapon simply discharged unpredictably while two people struggled for control.
Smith offered that account himself. He took the witness stand and testified that the argument with Brice intensified inside the car. He said Brice had a handgun and pointed it toward him before later turning it toward herself. Smith said he reached for the weapon and that it fired during the struggle. According to his testimony, the gun had been modified with a device that allowed extremely rapid fire.
The defense used that alleged modification to explain how several rounds could have been discharged within a short period. Smith maintained that the burst of gunfire was accidental and that he did not decide to kill Brice. His attorney argued that what Smith did after the shooting, while criminal, should not automatically prove what his state of mind had been at the moment the shots were fired.
That argument required Smith to acknowledge a series of damaging facts. He did not call 911 or seek medical assistance for Brice. He admitted helping dispose of her body and participating in the destruction of his Ford. He said he acted that way because he feared authorities would never believe his account of an accidental shooting. Prosecutors asked jurors to draw the opposite conclusion.
Crump argued that Smith’s actions were not the behavior of someone suddenly confronted with a tragic accident. Prosecutors said the evidence showed a series of deliberate choices: moving Brice’s body, recruiting help, using another vehicle, obtaining gasoline, burning the Ford and leaving Pennsylvania. The state’s theory was that the cover-up made sense because the shooting itself had been intentional.
Garnett provided direct testimony supporting part of that theory. She was arrested in 2021 and later pleaded guilty to offenses connected to concealing Brice’s body and destroying evidence. At Smith’s trial, Garnett testified that Smith told her he had shot Brice. She also described helping him afterward. Defense attorney Samuel Stretton challenged Garnett’s credibility and argued that her own legal interests gave her a motive to make Smith appear more culpable.
That challenge made the independent evidence important. Even if jurors questioned portions of Garnett’s account, prosecutors could point to video, cellphone records, blood evidence, cartridge casings and the medical examiner’s findings. The prosecution presented those facts as a framework that did not depend on accepting every word from any single witness.
The investigation also produced evidence of flight. Philadelphia authorities issued a warrant for Smith’s arrest April 9, 2021. Prosecutors said Smith and Garnett traveled to Miami after Brice’s death and that Smith hoped to reach Cuba. He did not return to face investigators. Instead, he eventually made his way to the Atlanta area, where he remained for years.
Federal authorities charged Smith with unlawful flight to avoid prosecution in 2023. The FBI joined a search involving agencies across several states. His fugitive period finally ended in March 2025, when Atlanta police encountered him during a traffic stop. Reporting on his arrest said officers stopped a vehicle over an expired registration and that Smith gave a false name before fleeing. He was eventually captured and identified.
Smith’s return to Philadelphia allowed prosecutors to place the accumulated evidence before a jury. Their presentation effectively moved through the case in stages: Brice’s final movements, the shooting evidence, activity at the garage, the use of the Hyundai, the burned Ford, recovery of Brice’s body and Smith’s departure from Pennsylvania. The defense, meanwhile, asked jurors to focus on whether any of those later acts could prove beyond a reasonable doubt that the original shooting was intentional.
The jury concluded that they could, when considered alongside the medical and forensic evidence. Smith was convicted of first-degree murder, meaning jurors found the killing was intentional and premeditated. He was also convicted in the death of the unborn child and of the crimes prosecutors said formed the cover-up.
Brice’s family attended the proceedings after waiting years for Smith to be captured. Her mother, Betty Cellini, said the killing left Brice’s older son without his mother. Brice had worked as a caregiver, hoped to become a dialysis technician and was preparing for a gender-reveal celebration. She died before learning that the baby she was carrying was another boy.
With Smith now sentenced to life without parole and an additional 40 to 80 years, the same evidence trail investigators once used to identify, locate and prosecute a fugitive has become the record supporting his murder conviction. The case that began with a missing woman and a burned vehicle has ended with a final judgment in a Philadelphia courtroom.
Author note: Last updated October 17, 2026.