Court records are giving more details on the days before two University of South Florida doctoral students went missing and why a roommate faces murder charges in theiir deaths.
An affidavit shows Hisham Abugharbieh asked the AI tool ChatGPT about body disposal and bought items like black trash bags before Zamil Limon and Nahida Bristy were reported missing. Investigators allege he fatally stabbed the couple, cleaned up the scene and concealed their bodies before disposing of them.
Limon and Bristy, both 27, disappeared from campus on April 16. The couple was originally from Bangladesh, but were attending USF on student visas. Limon was studying geography, environmental science and policy, and Bristy was studying chemical engineering.
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The Hillsborough County Sheriff's Office said Limon's body was found Friday on the Howard Frankland Bridge. If you were around that area on April 17 between 1 a.m. and 5 a.m., detectives are asking anyone with dash camera video or information to reach out at 813-247-8200.
Law enforcement also report recovering unidentified human remains from water near Interstate 275 and Fourth Street North in St. Petersburg over the weekend. Based on evidence, it is not believed Bristy is still alive, according to the affidavit.
Abugharbieh, 26, was Limon's off-campus roommate. He was once a USF student but is not currently enrolled. University records showed he had attended the university from spring 2021 through spring 2023, and had pursued a Bachelor of Science in Management, a university spokesperson said.
Abugharbieh faces two counts of first-degree murder, unlawfully moving a dead body, failure to report a death, tampering with evidence, false imprisonment and battery.
The false imprisonment and battery charges have to do with a separate case on Friday involving a family member, according to a Marsy's Law affidavit.
Timeline of investigation
The case was first flagged to law enforcement on April 17, when one of Bristy's friends went to the University of South Florida Police Department and explained that neither Bristy nor Limon could be contacted. Both of their phones were going to voicemail.
The friend had also gone to Limon's apartment to try to find him. The friend instead found another one of Limon's roommates, who had no involvement in the case. The roommate explained how he did not know where Limon was, as his scooter was still at the apartment. Limon's door was also locked, and they did not get an answer when they knocked.
On April 18, USF police went to Bristy's workplace. Several personal items, like her lunchbox and MacBook, were there. A larger purse was also still in the office along with an iPad.
Investigators reviewed surveillance footage the showed Bristy leaving her building on April 16 around 12:08 p.m. wearing a light pink, long-sleeve shirt, long black loose pants and sneakers with white bottoms. She was last seen on video walking north from her office on campus while holding an umbrella.
Limon's other roommate said he last saw Limon the evening of April 15, cooking rice. Limon's scooter was still there when the roommate left the apartment.
In an effort to locate Limon, USF police pinged his phone and saw how the device's location began on USF Genshaft Drive before moving toward the Courtney Campbell Causeway and then Clearwater Beach, where it remained.
The Hillsborough County Sheriff's Office was notified on April 18. Detectives then interviewed Abugharbieh and Limon's other roommate. The other roommate had a consistent account of when he last saw Limon.
According to the affidavit, Abugharbieh denied having knowledge of Limon's or Bristy's locations. He also had a wrapped cut on his left pinky finger. He told investigators he was injured cutting onions and initially wrapped it with duct tape and toilet paper.
ALSO READ: Roommate of one of the missing USF doctoral students charged with two counts of murder
Abugharbieh told investigators he drove a white Hyundai Genesis G80. And when the vehicle tag was searched, it showed his car was driving west on the Courtney Campbell Causeway within 10 minutes of when the same ping location was found on Limon's phone. The car was also in Clearwater Beach around the same time Limon's phone was pinged there.
Investigators said they did a follow-up interview with Abugharbieh, and his story shifted. According to court documents, he initially said the couple had never been in his car, nor did he go to Clearwater. However, once confronted with the phone and vehicle tracking, he said he went there to look for fishing spots. He told investigators that Limon asked to be driven with his girlfriend, and he dropped them off and left, returned home and did not go anywhere else. He did not explain why the coupled wanted the ride.
He maintained that he got injured cutting onions but said he could not remember what he was cooking.
Search history, ChatGPT evidence
According to an affidavit, the suspect bought duct tape from Amazon on April 7.
On April 11, he ordered fire starter, charcoal, trash bags and lighter fuel. He also had a DoorDash order for Lysol wipes and Febreze.
According to the affidavit, on April 13 he asked ChatGPT: "What happens if a human has put in a black garbage bag and thrown in a dumpster?" The AI chatbot provides an answer. He then asks, "How would they find out?"
According to investigators, over the next few days before Limon and Bristy were reported missing, Abugharbieh continued to ask ChatGPT questions, including, "Can a VIN number on a car be changed?"
On April 17, another ChatGPT search asked: "Are cars checked at the Hillsborough River state park."
The ChatGPT use ended until April 19, when it was asked about whether neighbors would hear a gun and if Apple will know whom a new iPhone user is after the previous one.
"Is there a water temperature that burns immediately," an April 19 ChatGPT search asked.
And finally, on April 23, another ChatGPT inquiry: "What does missing endangered adult mean?"
Based on these details, Florida Attorney General James Uthmeier announced on Monday in a X post that they are expanding their criminal investigation into OpenAI to include the USF murders.
🚨Suspect Faces Additional Charges🚨
— HCSO (@HCSOSheriff) April 25, 2026
Hisham Abugharbieh, 26, is additionally facing two counts of murder in the first degree with a weapon (premeditated) in the deaths of Zamil Limon and Nahida Bristy.
Evidence was presented to the State Attorney’s Office, resulting in further… pic.twitter.com/ELACGoJRLD
Physical evidence
Through a warrant, Abugharbieh was photographed and found with lacerations on both legs and a wound on his left upper tricep area.
Blood evidence was found in the apartment from the entry way through the kitchen, into the hallway and toward Abugharbieh's bedroom. In his room, there appeared to be "two distinct patterns" on the floor that appeared to be "relatively human-sized shape," that were consistent with smearing and dragging, the affidavit read.
There was also a box of heavy-duty black trash bags and lighter fluid found under the bed, and duct tape was in Abugharbieh's bathroom, the affidavit read.
The other roommate said he saw Abugharbieh late April 16 and the morning of April 17, moving cardboard boxes within his room to the apartment's compactor dumpster. When asked, Abugharbieh said he removed old clothing he no longer wanted. The affidavit said it also appeared Abugharbieh's vehicle was recently cleaned.
An April 23 search of the compactor showed several items that tested "presumptively positive" for blood. Those include a black cushion floor mat, a gray shirt with holes and cuts on it, gray shorts, tan slides and more. A light pink iPhone case consistent with a photograph of Bristy was also found.
A small bunny clutch was found in Limon's room with Bristy's USF identification and credit cards, which suggested to investigators that she was at the apartment before she went missing.
When law enforcement found Limon's remains on the side of the Howard Frankland Bridge on Friday, it was within numerous black utility trash bags. Based on the evidence of Limon's autopsy, it is believed that the couple died from multiple stab wounds, investigators reported.
"No evidence has been uncovered during the course of the investigation to support any probability Nahida Bristy remains alive," the investigators' report reads. "Based on the totality of the circumstances, interviews, evidence, and data, evidence would show Hisham Abugharbieh utilized a bladed instrument to fatally wound Zamil Limon and Nahida Bristy multiple times which caused their deaths."
Information from the Associated Press contributed to this report.
