How investigators say the killings of two University of South Florida students unfolded

Nahida Bristy and Zamil Limon
Nahida Bristy/Facebook/Family of Zamil Limon

As the suspect accused of killing two doctoral students in Florida faces murder charges, authorities have laid out disturbing and grisly details surrounding the students’ disappearance.

Zamil Limon and Nahida Bristy, both 27 and originally from Bangladesh, were last seen nearly two weeks ago in Tampa. Limon’s body was found a week later, and investigators believe Bristy was also killed. Her body has not been found.

Hisham Abugharbieh, Limon’s roommate, has been charged with two counts of first-degree premeditated murder with a weapon in the deaths of the students. A judge ruled Tuesday he will remain in detention as he awaits trial.

In a motion prosecutors filed last week to keep Abugharbieh, 26, in jail while he faces the charges, they laid out a detailed timeline of how investigators think the two University of South Florida students may have died as well as their and the suspect’s actions around the time they went missing.

Here’s a look at what they say unfolded.

April 7 & 11: Amazon purchases

Abugharbieh allegedly makes several purchases on Amazon, including duct tape, trash bags, lighter fuel and fire starter, according to the arrest warrant affidavit in the case.

April 13: A ChatGPT conversation

A ChatGPT conversation cited in the motion for pretrial detention shows Abugharbieh asks: “What happens if a human has a put in a black garbage bag and thrown in a dumpster,” to which the chatbot responds that it sounds dangerous.

“How would they find out,” Abugharbieh replies, according to prosecutors.

April 16: Last contact with the two students

Friends of Limon and Bristy are in touch with them during the day, but they can’t reach them later, according to the motion filed by prosecutors Saturday in Hillsborough County Court. Bristy and Limon speak briefly on the phone several times.

Around midday, Bristy is seen on surveillance video walking on the university’s campus, according to the motion. But she doesn’t show up to a planned meet-up that evening with a friend to get her eyeglasses and doesn’t answer the friend’s calls.

Limon’s phone location shows him in the vicinity of his home and campus before going to Clearwater – roughly 32 miles from his residence – around 7:43 p.m.

Abugharbieh’s white Hyundai Genesis G80 is seen traveling in the same area within about 10 minutes of that, according to prosecutors.

Phone and traffic data show consistencies between the suspect’s and Limon’s devices’ locations throughout the night.

About 10:30 p.m., a DoorDash order for trash bags, Lysol wipes, Febreze and other items from CVS is placed from Abugharbieh’s phone and delivered to the apartment door about half an hour later.

Limon and Abugharbieh’s other roommate sees Abugharbieh using a cart to move cardboard boxes from his room to a compactor dumpster at their apartment complex, according to the motion.

April 17: Students reported missing

A missing persons flyer for two University of South Florida students released by the Hillsborough Co. Sheriff Office
Hillsborough Co. Sheriff Office

A ChatGPT search on Abugharbieh’s phone asked “are cars checked at the Hillsborough River state park,” the affidavit says.

The suspect goes to the Howard Frankland Bridge – a strip of I-275 spanning Tampa Bay – twice between 1 a.m. and 4:30 a.m., according to the affidavit, citing phone and traffic data.

Meanwhile, Limon and Bristy are officially reported missing.

The next day, police search Bristy’s campus workplace and find she left personal items including her lunchbox, a MacBook and her iPad.

April 22: Investigators question suspect’s mother

Authorities speak with Abugharbieh’s mother, who says she last saw her son Saturday, April 18, the motion reads. She mentions Abugharbieh struggles with anger management and was violent with his family in the past, according to the document.

The suspect was arrested twice in 2023 on charges of battery, which were later dropped, according to court records. But after one of those incidents, his brother filed for an injunction that prohibited Abugharbieh from coming near him or his home. When the injunction expired last May, a request for extension was denied.

April 23: Searches underway

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

The Hillsborough County’s Sheriff’s Office elevates the status of the two missing students to “endangered.”

Authorities search a dumpster, in which they find a black cushion floor mat with blood, Limon’s wallet, Bristy’s phone case, Limon’s glasses and clothing all stained with blood. Around this time, Abugharbieh gives authorities permission to search his car, which prosecutors say appeared to have “recently been cleaned.”

Abugharbieh also lets investigators access the vehicle’s data, but there didn’t appear to be any, the affidavit said.

Abugharbieh gives inconsistent accounts of when he last saw Limon and Bristy, according to the affidavit. He first tells detectives the pair had “never been in his vehicle nor did he go to Clearwater.” When confronted about his vehicle being in Clearwater, he says he went there to look for fishing spots and later changed his story again, telling detectives Limon had asked to be driven with his girlfriend to Clearwater, the document says.

During these interviews, Abugharbieh’s left pinky finger is wrapped in a bandage, a wound he later says he got while cutting onions, the motion says. Detectives also observe a fresh laceration on his left upper tricep and additional cuts on both legs, according to the filing.

Prosecutors say Abugharbieh asked ChatGPT on April 23, “What does missing endangered adult mean.”

April 24: Limon’s body found, suspect arrested

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

Detectives searching the Howard Frankland Bridge find a black trash bag where phone data shows the suspect stopped early on April 17, according to the motion.

Prosecutors say the bag is similar to those found under Abugharbieh’s bed. A man’s remains are discovered inside and positively identified as Limon, they say in the filing.

Limon’s death is ruled a homicide, the motion states, citing “multiple sharp force injuries,” and a medical examiner’s report that noted a deep stab wound to his lower back that penetrated his liver, among other wounds.

That morning, Abugharbieh is arrested hours later at a home in Lutz, Florida, after law enforcement respond to a domestic violence incident involving a family member, the sheriff’s office says.

April 25: Suspect appears in court and detailed evidence is unveiled

Hisham Abugharbieh appears in court via video on Saturday, April 25, 2026, in Tampa, Fla.
WFTS-TV/AP

The pretrial motion is filed, with prosecutors alleging Abugharbieh made the purchases on Amazon and citing his alleged ChatGPT conversations.

Abugharbieh makes an initial appearance in court Saturday morning.

In addition to two counts of first-degree murder, he faces charges of unlawfully moving a dead body, failure to report a death with intent to conceal, tampering with physical evidence, false imprisonment and battery, the Hillsborough County Sheriff’s Office says.

The Hillsborough County Public Defender’s Office says it is appointed to the case but declines to share details, citing Abugharbieh’s right to a fair trial.

“We remain focused on representing our client through the legal process,” the office says in a statement.

April 26: Human remains found in waterway

Deputies from the Hillsborough County Sheriff’s Office say they recovered human remains from the waterways near Howard Frankland Bridge and are working to identify the remains.

April 27: Killings added to investigation into OpenAI

The state of Florida expands its criminal investigation into OpenAI, the parent company and creator of ChatGPT, to include the killings of Limon and Bristy, Florida Attorney General James Uthmeier announces.

“This is a terrible crime, and our thoughts are with everyone affected,” OpenAI spokesperson Drew Pusateri says in a statement. “We’re looking into these reports and will do whatever we can to support law enforcement in their investigation.”

Uthmeier said last week his office is looking into whether ChatGPT helped the suspect in a deadly shooting at Florida State University carry out the crime and “whether OpenAI bears criminal responsibility for ChatGPT’s actions.”

April 28: Suspect held without bond

A status conference is held to determine how the case against Abugharbieh will proceed.

Hillsborough County Judge J. Logan Murphy grants the prosecutors’ request to hold Abugharbieh without bond on the two first-degree murder charges as he awaits trial. Abugharbieh does not appear in court for the meeting, according to Erin Maloney, a spokesperson with the State Attorney’s Office.

An arraignment has yet to be scheduled.

⚠️ NEW DETAIL EMERGES: Communication records show that Nahida Bristy and Zamil Limon exchanged numerous messages that day — and the last message recovered by investigators was a single short sentence sent at 9:58 PM.

The investigation into the tragic deaths of University of South Florida doctoral students Zamil Limon and Nahida Bristy has taken another harrowing turn as digital forensic teams peel back the layers of their final communications. While the arrest of Hisham Abugharbieh provided a name for the suspect, the “why” and the “how” remain locked within the encrypted fragments of the victims’ digital lives. The latest breakthrough comes from a meticulous reconstruction of communication records which reveals that the couple was in constant, almost frantic contact throughout the day of their disappearance. This stream of digital consciousness, which had been a lifeline between two scholars deeply in love, ended with a chilling abruptness that has left investigators and the community reeling. The final message, sent at 9:58 PM, consists of a single short sentence that stands as a haunting period at the end of their lives, raising profound questions about the exact moment the situation transitioned from a state of concern to one of absolute catastrophe.

The sheer volume of messages exchanged between Nahida and Zamil on that fateful day suggests a state of heightened anxiety or a rapidly evolving situation that required constant coordination. Friends and family describe the couple as being highly communicative, but the frequency of these specific logs reportedly exceeded their normal patterns. This suggests that even as they moved between campus buildings and their respective residences, they were navigating a shared crisis. Hypothetically, if Zamil had already begun to feel that “something was off” at his apartment, these messages likely served as a real-time tether to Nahida, who was balancing her own academic demands with a growing sense of dread for her partner’s safety. The digital trail suggests a couple trying to find a way to navigate a threat they might have sensed but had not yet fully escaped, creating a virtual map of their movements and emotional states in the hours leading up to the final silence.

The discovery of the 9:58 PM message has become the new “ground zero” for the investigative timeline. In the absence of the message’s specific content being released to the public, several chilling hypotheses have emerged. One theory suggests the message was a final, desperate instruction or a warning. Given the proximity to the time they were believed to have been intercepted, this single sentence could have been a directive to “don’t come here,” “call the police,” or a simple, heartbreaking “I love you” sent in a moment of realization that escape was no longer possible. If the message was sent by Nahida to Zamil, it could indicate she was the one witnessing a brewing confrontation; if sent by Zamil to Nahida, it might have been his last attempt to shield her from the violence he was already facing. The brevity of the communication—a single short sentence—implies an extreme lack of time, a message typed with trembling hands or under the immediate duress of an approaching shadow.

Another darker hypothetical scenario explores the possibility that the final message was not sent by either victim at all. Forensic experts are reportedly examining the metadata to determine if the cadence and linguistic style of the 9:58 PM text match the thousands of messages that preceded it. There is a terrifying possibility that the perpetrator, having already gained control over one or both phones, sent a final message to lure the other victim into a trap or to create a false sense of security for anyone who might be looking for them. If the message said something as simple as “Going to sleep now” or “See you tomorrow,” it could have been a calculated move to buy the killer hours of lead time before a search was officially initiated. This would transform the final communication from a cry for help into a weapon of deception used to seal the fate of the two scholars.

The impact of this 9:58 PM timestamp on the USF community is immeasurable, serving as a grim reminder of how quickly a life can be extinguished in the digital age. For the students who walked the same halls and shared the same aspirations as Zamil and Nahida, the thought of that last message sitting in an outbox while the world continued to turn is a source of profound existential dread. The university, usually a place of endless dialogue and the pursuit of truth, is now defined by this singular, unfinished conversation. The image of the phone screen, glowing with a final sentence that was never answered, has become the defining icon of the tragedy—a symbol of a connection that was violently severed just as it was most needed.

As the legal proceedings against Abugharbieh enter a critical phase, these communication records will likely form the backbone of the prosecution’s case for premeditation. The transition from “numerous messages” to a “single short sentence” and then to total silence provides a digital fingerprint of a crime in progress. While the public waits for the contents of that final 9:58 PM message to be revealed in court, the hypothetical weight of those words continues to hang over the campus. It is a sentence that marks the end of two brilliant careers, a shared dream of a future in science, and the final heartbeat of a relationship that ended in a tragedy that 2000 words can barely begin to encompass.