Slain University of South Florida doctoral student Zamil Limon once complained about the “psychopathic” roommate now accused of killing him and his still-missing girlfriend, relatives revealed Monday — while demanding the “highest possible punishment” for the couple’s alleged murderer.

“He barely [knew] Hisham Abugharbieh, but he always informed us that his roommate is kind of unsocial, unpleasant and sort of psychopathic behavior,” Limon’s brother, Zubaer Ahmed, told KLFY 10 News.

Once, things got so uncomfortable around their shared off-campus home — which was part of a residential complex called Avalon Heights — that Limon and a third roommate named Rashid filed a formal complaint against Abugharbieh, according to the relative.

“It’s very unfortunate or unbelievable that Avalon Heights didn’t consider it seriously or [take] necessary steps,” Ahmed told the outlet.

Abugharbieh, 26, faces two first-degree murder charges for allegedly killing Limon and his girlfriend, Nahida Bristy, both 27, earlier this month.

Limon’s body was found Friday on the Howard Frankland Bridge, which spans from St. Petersburg to Tampa, while Bristly remains missing, but is presumed dead.

“I miss everything about him: his smile, his anger, his fight with me,” Limon’s brother continued. “I remember everything. Yeah. I just wanted to know that he is very hardworking, kind and full of dreams.”

Families for the victims — who were both Bangladeshi students studying for their doctorate degrees at USF that dreamed of getting married one day — said Abugharbieh should be prosecuted to the fullest extent of the law.

“We demand the highest possible punishment under the law for Hisham Saleh Abugharbieh, along with anyone else who may be connected, and request that the legal process move forward as quickly as possible,” read their joint statement released Monday, according to KLFY 10.

The families also called for legal action against Avalon Heights, which they said lacked “proper CCTV camera” usage and insufficient security measures to protect residents.

They further blamed the housing complex for assigning Abugharbieh as Limon’s roommate without background checks, the outlet reported.

Avalon Heights didn’t immediately respond to requests for comment.

The Bangladesh-based relatives said they wanted Limon and Bristly’s remains to be “handled in accordance with Islamic rituals and funeral requirements,” and for their personal belongings to be returned to their loved ones.

The families reportedly called for the university’s help in ensuring their wishes are fulfilled — and to establish a memorial at USF in Limon and Bristy’s honor, aimed at preventing such tragedies in the future.

Prosecutors have not revealed a motive in their case against Abugharbieh, who allegedly asked ChatGPT about putting people in a dumpster, changing a car’s VIN number and firearm licensing in the days surrounding the couple’s April 13 disappearance.

He was arrested Friday after cops rushed a Tampa home responding to an unrelated domestic violence incident, Hillsborough County Police said. He barricaded himself inside the property and refused to cooperate for over an hour, until finally surrendering to authorities — while wrapped in just a blue towel.

Investigators found blood splatters inside Abugharbieh and Limon’s home and said Limon suffered “multiple sharp force injuries” while being killed. His wallet was later found in a trash compactor, as well as glasses and a pink iPhone case belonging to Bristy.

Abugharbieh is due to appear in court on Tuesday.

He also faces charges of unlawfully holding or moving a dead body in unapproved conditions, failure to report death, tampering with physical evidence, false imprisonment and battery.