Four months after the Melbourne 35-year-old disappeared, a new police review is focusing on video from the hotel for new insights into his last movements.

The investigation is being followed with keen interest by Mr Bogar's friends and his mother Rozalia Bogar, who said she hadn't lost hope of seeing her son again.

"I still feel he's alive," she said.

"I don't know why he left his car, and why he left everything in his car.

"He loved me very much, I know that. Either he can't call me or he doesn't want to call me - but I don't believe it. Maybe he was kidnapped, I don't know."

Mr Bogar left Avondale Heights about 3am on October 9.

He had no connection to the Illawarra but appears to have checked into the city's Chifley Hotel on October 9 or October 10.

Family friend Carly Heard said Mr Bogar had been under work-related pressure and was decreasing his dosage of anti-anxiety medication in the lead-up to his disappearance.

In the past, the condition had caused him to feel uncomfortable driving, Ms Heard said.

"I think that [decreased dosage] could have altered his state of mind," she said. "It seems most likely that he may have had a panic attack and wasn't able to drive. I've got no idea what happened [next]."

A police investigation began when Mr Bogar's silver Audi was reported abandoned on October 17.

It focused on the possibility he had entered bushland off Picton Road, near Cataract and Cordeaux Dam, and either intentionally or unintentionally died. An extensive two-day search, involving 150 police, SES, Polair, dog squad, Volunteer Rescue Association and RFS personnel yielded nothing, as did two subsequent searches, one of which was carried out with a cadaver dog.

Wollongong detective Kevin Bale called on anyone who may have been at the Chifley around the time of Mr Bogar's stay and believe they may have seen him to contact Crimestoppers on 1800 333 000.