LAS VEGAS -- Las Vegas police searched Mike Tyson's home Wednesday after a sexual assault allegation was made against the former heavyweight champion.

No charges have been filed against Tyson, but police searched his home for evidence related to a recent sexual assault in Nevada, police Lt. Tom Monahan said.

"He is the one identified by the accuser," Monahan said. "This was only one step in a very lengthy investigation. No arrests are imminent."

No details about the allegation or Tyson's accuser were available, Monahan said, because the investigation is ongoing.

When police finish their investigation, they will turn over any evidence they collect to the Clark County district attorney's office to determine whether charges will be filed, Monahan said.

A police SWAT team surrounded Tyson's home before the warrant was served around 1 p.m. as a precaution because of the high walls around the nearly two-acre estate, Monahan said.

"It's a pretty standard procedure," he said.

The 35-year-old Tyson was cooperative with police, Monahan said.

Tyson's $1.3 million home is on the city's southeast side, next to the estate belonging to Las Vegas Strip headliner Wayne Newton.

It is the second sexual assault allegation involving Tyson this year.

In August prosecutors said there wasn't enough evidence to charge Tyson after a California woman accused him of rape.

Arlene Moorman, 50, alleged Tyson sexually assaulted her July 16 in a home he was renting near Big Bear Lake.

San Bernardino prosecutors said the case was given close scrutiny because of Tyson's reputation for violence and a 1992 rape conviction in Indiana for which he served three years in prison.

The sixth-ranked heavyweight is training in Las Vegas for his Oct. 13 fight in Copenhagen against Danish boxer Brian Nielsen.

Tyson's publicist said he was not aware of the police search and had no comment.