Noted cricket columnist Peter Roebuck was about to be detained over an alleged sexual assault on a Zimbabwean Facebook friend when he committed suicide at his hotel, in Cape Town, his colleague Jim Maxwell has said.

The 55-year-old commentator plunged to death from his sixth floor room in the Southern Sun Hotel but Western Cape provincial police have till now refused to say whether reports that he was being questioned on sexual assault charges were true.Maxwell, a fellow commentator with the ABC radio, was the last of Roebuck's friends to see him alive on Saturday night and has given some details about his friend's last moments.

He told AM radio that the police confirmed to him they were there to detain Roebuck over an alleged sexual assault on a Zimbabwean man who had made the complaint against the respected commentator.

"I'm sure what happened was triggered by the visit of the police and the fact that they were going to charge him with an alleged sexual assault, which meant he was going to be detained and would then have to appear in court on Monday," Maxwell said.

"This is what I discovered when I went to his room after he made a very agitated, dramatic, despairing phone call to my room. He was absolutely on edge."

"When I arrived the detective came out and filled me in on the details. It was then that I asked if I could speak to him (Roebuck) and the detective said 'well, just for a moment', because clearly they didn't want their case compromised in some way, I suppose, by what he may have said to me.Maxwell said he was only a few moments with Roebuck before he took the extreme step."

 "So I only had a few moments with him. He was desperate to get in touch with all those students that were in his care in Pietermaritzburg. He didn't have a phone number", Maxwell said.

"He asked for a lawyer and I said I'd see what I could do after which I made a reference to John Fairfax, his main employer. He said you won't have to do that because they'll know."

Maxwell said he then left the room, along with one of the two policemen who had been sent to detain Roebuck.

"I'm trying to piece this together, but I'd say that it [Roebuck's death] probably happened fairly quickly," he was quoted as saying in the media."

"If it's the case that there was only one policeman in the room, I'm inclined to the belief that, sadly, when I left the room and the detective came out with me -- because I wanted to get his mobile phone number so I could ring him -- it may have occurred there and then.Maxwell said he realised something untoward had happened when he heard the detective talking on his mobile phone to someone about a complication."

"Because I then moved down the corridor to speak to one of my colleagues, and I was standing in the doorway telling him what had occurred, and within a matter of a minute I could hear outside the lift the detective talking on his mobile phone to someone about how there'd been a complication."

"And in trying to make out what he was saying it sounded like someone had gone out the window and that person, sadly, was dead," he said.Police said that an inquest has been launched into Roebuck's death and it may take four to eight weeks for it to be completed."

"An inquest can take a long time, it can be anything from six months to two or three years, but what is critical here is to get the autopsy reports, or what we call the post-mortem report," Colonel Vishnu Naidoo said.

Meanwhile, Roebuck's mysterious personal life has become a subject of speculation after his suicide with a radio host claiming that the celebrated journalist made him feel "uncomfortable" and acted "inappropriately" during an interaction.