Jay McManus, 61, who was known as Big Jay to friends and family, died Sunday night at Long Beach Memorial Hospital from critical injuries he sustained on Aug. 14 after leaving Avenue 3 Pizza in East Long Beach.

Alongside the pain the family has felt in the wake of McManus’ death, there is also a sense of frustration and confusion as investigators have not been able to clearly say what happened the night before McManus was found unconscious.

Though police have not confirmed the circumstances leading to his death, the case is being investigated by the department’s homicide detail, police said in a press release Tuesday afternoon.

McManus was found with trauma to the front and back of his head, neck and “scuffs and bruises all over his body,” according to friends and family, who believe Jay was assaulted and robbed because he was also found without clothes and his wallet and watch were missing.

Jimmy McManus, Jay’s son, said two homicide detectives are in contact with the family and are investigating the cause of his father’s fatal injuries. They told him the coroner’s autopsy report would take about two weeks to complete.

On Tuesday, a spokeswoman for the coroner’s office said in an email that they were waiting on more information from the hospital.

Police said a potential battery incident was reported on Aug. 16 after they received a call from Jimmy who said his father may have been assaulted on Aug. 15 and was at the hospital.

McManus was found lying in a service road near Stearns Street and Carfax Avenue in the Los Altos South neighborhood around 4:45 a.m. on Aug. 15 with a critical injury to the upper body, according to police.

According to police, McManus was last seen walking alone from Avenue 3 Pizza at approximately 10 p.m. on Aug. 14. At some point between 10 p.m. and 4:46 a.m., he sustained a “critical injury” to his upper body, however, it is currently unknown how he sustained the injury, police said.

His property has all been located with the exception of a watch, police said.

Investigators are zeroing in on the hours between 10 p.m. the night of Aug. 14 and 4:46 a.m. early next morning.

Police urged anyone who lives in the area to review their camera footage between those hours for any photo or video evidence that may have captured what occurred that night.

This past weekend, Jay’s friends and family hosted a gathering at Avenue 3 Pizza to share fond memories.

“It was bitter sweet,” Jimmy said. “People had nothing but good things to say about him.”

The man was admired by Jimmy’s friends who grew up without fathers. They saw him as their father figure, and called him Big Jay, Jimmy said. Rex Marshall, a close friend of the family, has started a GoFundMe for the family to help pay for hospital bills.

Jimmy said he went back to work Tuesday to get his mind off of what happened, but the incident has taken a heavy toll on the family.

“It’s just been tough,” he said.

Family of hospitalized East Long Beach man to host fundraiser at Avenue 3 Pizza