A star government witness in the Barry Bonds perjury trial took the stand Wednesday morning and testified that the slugger ordered him in 1999 to research the effects of a steroid.

Steve Hoskins and Bonds grew up together in San Mateo County. As adults, Hoskins had a bitter falling out with Bonds while serving as his business partner.

Hoskins said he initially served as a kind of valet when Bonds began playing with the San Francisco Giants in 1993, lugging equipment to the ballpark and running personal errands for the slugger.

Under questioning from federal prosecutor Matt Parrella, a jittery Hoskins testified that in 1999 Bonds ordered him to research the benefits and side effects of the steroid Winstrol.

By Paul Elias, Associated Press