New York ? Baseball began its investigation Thursday into alleged steroid use by Barry Bonds and others, and the head of the inquiry immediately came under attack because of his close ties to the sport.

In the wake of a searing book about Bonds, commissioner Bud Selig appointed former Senate Majority Leader George Mitchell – and currently a director of the Boston Red Sox – to lead the investigation.

The probe initially will be limited to events since September 2002, when the sport banned performance-enhancing drugs, but Mitchell has the authority to expand it.

Selig said Mitchell’s report will be made public but didn’t set a timetable.

“The goal here is to determine facts, not engage in supposition, speculation, rumor or innuendo,” Selig said.

Whatever the findings, it will be hard to penalize anyone for conduct before the steroids ban. Baseball began drug testing in 2003 and started testing with penalties the following year.

Mitchell said he will not resign his position with the Red Sox. He also is chairman of The Walt Disney Co., the parent of ESPN, a national broadcast partner of baseball.

“I don’t think there’s any conflict,” he said. “I’m going to be independent, have complete independent authority and will act.”

ESPN is airing a weekly behind-the-scenes look at Bonds – with the Giants star’s cooperation – starting next week.

Along with working for the Red Sox, Mitchell is a former director of the Florida Marlins and served on an economic study committee Selig appointed in 1999. He said he previously announced he would leave the Disney board by the end of the year.

“I’ve assured the Red Sox owners that should any matter arise, anybody affiliated with the Red Sox will be treated exactly as will anyone else,” he said.

John Dowd, the Washington lawyer who headed baseball’s investigation of Pete Rose’s gambling in 1989, did not like the choice.

“Mitchell doesn’t have a great track record with me. It doesn’t look like he’s independent,” Dowd said.

Selig’s decision came soon after “Game of Shadows,” a book by two San Francisco Chronicle reporters detailing alleged extensive steroid use by Bonds and other baseball stars.

Earlier Thursday, Victor Conte – founder of the Bay Area Laboratory Co-Operative – was released from a California prison. He spent four months there after pleading guilty to orchestrating an illegal steroids distribution scheme that allegedly involved many high-profile athletes.

Asked whether he gave Bonds steroids, Conte said: “No, I did not.”