Investigators say a roommate has been charged with first-degree murder after one University of South Florida doctoral student, Zamil Limon, was found dead and another, Nahida Bristy, remains missing. Prosecutors cite phone and vehicle data, surveillance footage, alleged Amazon purchases of duct tape and trash bags, a DoorDash delivery, ChatGPT queries on the suspect’s phone, and bloodstained items recovered in a dumpster and near the Howard Frankland Bridge. The suspect is held without bond while authorities continue searching for additional evidence and remains, and Florida has expanded an inquiry into OpenAI’s role in related probing.
Roommate Charged After USF Doctoral Student Found Dead; Second Student Missing — Investigators Lay Out Timeline
Nahida Bristy and Zamil Limon - Nahida Bristy/Facebook/Family of Zamil Limon
Authorities have outlined a disturbing timeline in the disappearance and deaths of two 27-year-old doctoral students at the University of South Florida, as prosecutors accuse their roommate of murder. Investigators say digital records, surveillance footage, purchases and forensic evidence connect the suspect to the events surrounding the students’ disappearance.
Who Is Involved
Zamil Limon and Nahida Bristy, both 27 and originally from Bangladesh, were last seen in Tampa in mid-April. Limon’s remains were later identified; Bristy remains missing and is believed to be deceased. Their roommate, Hisham Abugharbieh, 26, has been charged with two counts of first-degree premeditated murder with a weapon and is being held without bond.
A missing persons flyer for two University of South Florida students released by the Hillsborough Co. Sheriff Office - Hillsborough Co. Sheriff Office
Prosecutors’ Timeline and Key Evidence
In a motion seeking to keep Abugharbieh detained, prosecutors laid out a sequence of events pieced together from phone and vehicle location data, surveillance footage, delivery records, witness statements and recovered physical evidence.
Digital Footprints and Purchases
Prosecutors say the suspect made online purchases that included duct tape, large trash bags, lighter fluid and fire starters. A DoorDash delivery placed from Abugharbieh’s phone around 10:30 p.m. allegedly brought trash bags, Lysol wipes and Febreze to the apartment.
The Hillsborough County Sheriff's Office Marine and Dive teams searching for missing University of South Florida doctoral student Nahida Bristy near the Howard Frankland Bridge in Florida. - Hillsborough County Sheriff's Office
Prosecutors also cite ChatGPT conversations found on the suspect’s phone in which he reportedly asks: “What happens if a human has a put in a black garbage bag and thrown in a dumpster” and later, “How would they find out.”
Movements and Surveillance
Surveillance placed Bristy on campus around midday the day they vanished; she missed a planned evening meeting to pick up eyeglasses and did not respond to calls. Phone-location data show Limon near his home and campus before traveling to Clearwater at about 7:43 p.m. Prosecutors say Abugharbieh’s vehicle was in the same area within roughly 10 minutes. Phone and traffic data indicate overlapping locations for Limon’s and the suspect’s devices through the night.
Searches and Forensic Findings
After the students were reported missing, deputies searched a dumpster and found a black cushion floor mat with blood, Limon’s wallet, Bristy’s phone case, Limon’s glasses and bloodstained clothing. Detectives later recovered a black trash bag near the Howard Frankland Bridge that phone records place the suspect at early on April 17. Human remains found inside were positively identified as Limon.
This still from a video released by Hillsborough County Sheriff's Office shows the moment the suspect was arrested in connection to the disappearance of two USF students. - Hillsborough County Sheriff's Office
The medical examiner ruled Limon’s death a homicide, citing multiple sharp-force injuries, including a deep stab wound to the lower back that penetrated his liver.
Interviews, Injuries and Prior Incidents
Investigators say Abugharbieh gave inconsistent accounts of when he last saw the students and whether they were in his vehicle. Detectives observed fresh cuts and bandaging on the suspect during interviews; he reportedly told them one cut occurred while slicing onions. Court records show two 2023 arrests for battery charges that were later dropped, and family members previously sought protective orders.
Hisham Abugharbieh appears in court via video on Saturday, April 25, 2026, in Tampa, Fla. - WFTS-TV/AP
Charges, Legal Proceedings and Broader Inquiry
In addition to two counts of first-degree murder, prosecutors say Abugharbieh faces charges including unlawfully moving a dead body, failure to report a death with intent to conceal, tampering with physical evidence, false imprisonment and battery. A judge has ordered him held without bond pending trial; an arraignment has not yet been scheduled.
Florida’s attorney general announced an expanded criminal inquiry into OpenAI to examine whether interactions with ChatGPT played any role in this case and another alleged deadly incident. OpenAI said it is cooperating with law enforcement.
Where the Case Stands
Investigators continue to search waterways near the Howard Frankland Bridge for additional remains and are working to identify recovered material. The Hillsborough County Public Defender’s Office has been appointed to represent Abugharbieh and declined further comment, citing his right to a fair trial.
Reporting notes: Prosecutors’ descriptions in a pretrial detention motion form the basis of the timeline; the suspect is accused but presumed innocent until proven guilty in court. CNN reporters Amanda Musa and Chris Boyette contributed to original coverage.
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