VANCOUVER - Justin Bieber usually stays cloistered in his hotel room when he's on tour and rarely ventures out to engage in typical teen activities like laser tag, says the author of a book about the pop superstar.

Chas Newkey-Burden was taken aback by published reports that Bieber had allegedly been involved in an altercation at a Vancouver entertainment complex.

"He tends to keep quite a quiet, wholesome life, and his mom's almost invariably ... out on the road with him anyway," Newkey-Burden, the author of "Justin Bieber: The Unauthorized Biography," said in a telephone interview on Monday.

"I think quite a lot of it is just sort of getting back to a hotel and sitting and chilling out and playing computer games or whatever."

Bieber, who's scheduled to play in Vancouver on Tuesday, has been met by mob scenes on several occasions in recent years, most notably when he was greeted at an Auckland, New Zealand airport in April by a group of overzealous fans who knocked over his mother, Pattie Mallette, and stole his hat.

Before that, a public Bieber performance in Australia had to be shut down by police after thousands of girls surged toward the stage (eight of the crowd members were sent to hospital) and appearances at malls in Long Island, N.Y., and Paris had to be aborted due to reports of out-of-control crowds.

Newkey-Burden says that Bieber thus tends to keep to himself and his close inner circle when on the road, and rarely ventures out.

"I think that he's had a very abnormal life in the last two years despite the fact that his mother and his management around him, I think, have done a pretty admirable job of keeping his feet on the ground," Newkey-Burden said.

"When you've seen your mother get knocked over in airports by fans and everything else that's come from fame, all the hysteria for him, at a very young age, he's understandably kept out of everyday things ... quite a lot."

RCMP are investigating allegations a 12-year-old boy was assaulted at an entertainment facility in suburban Vancouver by another boy, who media reports have identified as Bieber.

An RCMP news release says the 12-year-old's father filed a complaint after the incident in the suburb of Richmond last Friday.

Police say the boy suffered minimal injury and did not require medical attention.

On Monday, RCMP Cpl. Annie Linteau said the investigation is ongoing as police conduct interviews.

A gaggle of young, female Bieber fans gathered Monday outside the Vancouver hotel where he's staying, hoping to catch a glimpse or nab an autograph. Most said they think Bieber is innocent.

"He wouldn't do something like that, because that's not him at all," said Caitlin Dunfield, 15, who travelled with two friends from Victoria to see Bieber's concert.

"Yeah, he's just definitely a really humble, nice person and he wouldn't do that," agreed Michelle Fuller, 15.

But 12-year-old Destiny Hunter, from Vancouver, said she wouldn't mind hearing an apology, if warranted.

"(I want to hear) what truthfully happened, from his point of view," she said.

The celebrity gossip website TMZ.com quotes unnamed sources saying a boy went out of his way to target Bieber during a laser tag game.

A boy used a homophobic slur against Bieber, TMZ reported.

The site also says Bieber wants to launch an anti-bullying campaign in the wake of the alleged incident.

Newkey-Burden didn't comment on the specific details of the case, but noted that Bieber had always handled himself well when antagonized in public -- for instance, when he was struck by a water bottle during a show in Sacramento and responded by calmly asking why a fan would throw anything onstage.

"He's kind of on his own out there and it must be scary," Newkey-Burden said. "People compare it to Beatlemania. Well, the Beatles were a lot older than he is at the peak of their fame and there was four of them."