Ibraim Matos pleaded not guilty after prosecutors said a stolen vehicle struck and killed Mabinty Janneh on a busy sidewalk.
BOSTON, MA. — A Hyde Park man accused of carjacking a vehicle and killing a Dorchester woman on a Mattapan sidewalk was ordered held without bail Monday after pleading not guilty to murder and other charges.
Ibraim Matos, 37, appeared in Dorchester District Court after a Saturday afternoon crash that killed Mabinty Janneh, 32, of Dorchester, near Mattapan Square. The case now turns on both the criminal charges and a mental health review ordered by Judge Erika Reis. Matos was sent to Bridgewater State Hospital for an evaluation to determine whether he is competent to stand trial.
Prosecutors said the violence began shortly before 2 p.m. Saturday near Blue Hill Avenue and Woodhaven Street, when Matos crashed his own Acura and left the damaged vehicle. Suffolk Assistant District Attorney Ursula Knight told the court that Matos then ran to a nearby car wash, pulled a woman from her Toyota RAV4 and drove away. “He wreaked havoc on the Mattapan community,” Knight said during the arraignment. Authorities said Matos drove the wrong way on Blue Hill Avenue toward Mattapan Square before steering onto a sidewalk crowded with people on a sunny weekend afternoon.
Janneh had just gotten off an MBTA bus and was headed to a bank when the stolen SUV came down the sidewalk, prosecutors said. Knight said pedestrians tried to run into doorways and away from the vehicle, but Janneh could not escape. Prosecutors said she was struck, dragged several hundred feet and pronounced dead at the scene. Police said the stolen vehicle hit another vehicle near Blue Hill Avenue and Fairway Street, then continued until it crashed into an MBTA bus near 1629 Blue Hill Ave. Officers arriving at the scene found a large crowd around the vehicle and several community members restraining Matos.
Boston police identified the victim Monday as Mabinty Janneh. Family members called her “Binty” and said they were still trying to understand the sudden loss. Her cousin Ahmad Thorley spoke outside court with relatives nearby, some crying. “We are still saddened, shocked, and disturbed about this event and the loss of our loved one,” Thorley said. He also thanked people in Mattapan who helped stop the suspect after the crash. “We would like to thank the Mattapan community for intervening and preventing more loss of life,” he said. Authorities have not said what they believe led to the alleged carjacking and crash.
Matos is charged with murder, carjacking, leaving the scene of an accident resulting in death, leaving the scene of an accident resulting in personal injury and motor vehicle homicide by reckless operation. He pleaded not guilty to the charges. Prosecutors said he has a long criminal record, including cases that were largely domestic in nature and several restraining orders. Defense attorney Kevin Mullen did not address the facts of the case in detail after court. He said the defense would assess “where we stand” after the mental health evaluation. A court-appointed mental health professional told the court that an initial assessment raised questions about Matos’ psychological state.
The mental health review will be conducted at Bridgewater State Hospital, where doctors are expected to examine whether Matos can understand the charges and take part in his defense. The court was told that Matos reported post-traumatic stress disorder, and his attorney also raised possible schizophrenia and past hospitalizations. The evaluation does not decide guilt or innocence. It is a procedural step used when a defendant’s ability to stand trial is in question. Reis ordered Matos held without bail while the review moves forward and set his next court date for July 10.
The crash shook a busy stretch of Mattapan where Blue Hill Avenue carries bus riders, drivers, businesses and steady foot traffic. Witnesses described people running as the vehicle moved along the sidewalk. Victoria McGovern, who said she saw the start of the incident, told reporters the scene was horrifying. “It’s terrible. It’s absolutely disgusting,” she said. Another witness, Darline Duverne, said people did not know where the vehicle would go next as they tried to move away. The owner of Fernandez X-Press Car Wash said he was not there when the carjacking happened but later saw video from the scene.
Suffolk District Attorney Kevin Hayden called the episode “an instant nightmare in one of the busiest areas of our city.” He said the number of people nearby made the danger especially severe. “It’s impossible to overstate the peril posed by this man’s actions when so many people were out and about enjoying a beautiful summer Saturday,” Hayden said. He said prosecutors would seek justice for Janneh, her family and the Mattapan community. Police said the investigation began as officers responded to a report of a person struck and found Janneh unresponsive in the area.
A separate case was also opened after the crash scene was secured. Authorities said Robert Monestime, 21, of Braintree, was charged after allegedly entering the taped-off crime scene and filming while laughing. That case is separate from the murder and carjacking charges against Matos. Officials have not said whether more charges will be added in the main case. The next public step is the July 10 status review, when the court is expected to receive an update connected to the competency evaluation.
Matos remained held without bail Tuesday. Janneh’s family continued to grieve as prosecutors prepared for the next hearing and investigators reviewed video, witness accounts and crash evidence from the Blue Hill Avenue corridor.
Author note: Last updated June 23, 2026.