SAN FRANCISCO (AP) — Barry Bonds’ penchant for turning longtime friends into bitter enemies might come back to hurt him in at least two significant ways at trial.

First, there’s Steve Hoskins. He was once Bonds’ closest friend and served as best man at the slugger’s first wedding.

Then, there’s Kimberly Bell, the home run king’s girlfriend of 10 years, who dated him even after his first wedding. In fact, Hoskins’ sister introduced Bell to Bonds after a San Francisco Giants game in 1994.

Each had a nasty falling out with the notoriously prickly slugger, and each is now expected to be a key witness for the prosecution if Bonds goes to trial for perjury and obstruction of justice. He was indicted last week for allegedly lying when he told a federal grand jury he never knowingly used performance enhancing drugs, and is likely to face prison time if convicted.

Hoskins and Bell each claim to have firsthand knowledge of Bonds’ steroid use, making them extremely valuable witnesses. Yet both also are vulnerable to attack by Bonds’ lawyers because of their severed relationships with the former Giants star and their own personal problems.

“If they were standing alone, their credibility would present a big problem for the prosecution,” said Peter Keane, law professor at Golden Gate University in San Francisco.

“But the problem for Bonds is the collective amount of all this stuff the prosecution appears to have: the change in his body, the lab results. All of these things taken together make for a significant prosecution case against Bonds.”

Hoskins and Bonds were childhood friends, both growing up in San Carlos, a southern San Francisco suburb.

Their fathers were friends: Bonds’ dad played for several major league teams during a 14-year career, and Hoskins’ dad was a star lineman for the San Francisco 49ers.

They rekindled their friendship in 1993, when Bonds signed with the Giants as a free agent after spending the early part of his career in Pittsburgh.

Bonds made Hoskins his business manager and they launched a company called Kent Collectibles to sell Bonds’ memorabilia.

Things fell apart in 2003 after Bonds accused Hoskins of forging his signature on at least two contracts and selling memorabilia without Bonds’ permission.

Hoskins’ attorney has said Hoskins told federal investigators that Bonds was a heavy steroid user. When the lawyer, Michael Cardoza, went public last year with Hoskins’ tale he declined to discuss in detail how Hoskins knew about Bonds’ alleged steroids use.

Cardoza said Hoskins followed through on a threat to tell federal prosecutors about Bonds’ alleged drug use after the slugger complained to the FBI that Hoskins was stealing from him. Bonds did complain to the FBI, but the feds soon dropped their investigation of Hoskins and turned their sights on Bonds and his alleged steroid use.

“Stevie is going to get on the stand and tell the truth,” Cardoza said in a brief interview Tuesday. “Barry ignited this whole thing with Stevie.”