Kimberly Bell, a star prosecution witness in the former slugger's perjury trial, said the ex-Giant threatened to cut off her head after he began using steroids. Bonds' lawyer was admonished by the judge for her aggressive questioning of Bell.The former mistress of slugger Barry Bonds testified tearfully at his federal trial Monday that Bonds had threatened to cut off her head, cut out her breast implants and burn her house after he began using steroids about 2000, seven years before he broke the record for career home runs.