A man who refused to testify before a grand jury investigating O.J. Simpson's friend Al Cowlings was thrown in the slammer for contempt of court. John Dunton claims he would be afraid for his life if he testified. In one TV interview, Dunton said he had secondhand information that three people may have been at Nicole Brown Simpson's condo the night she and her friend Ronald Goldman were slain. BTW: Dunton has twice been convicted of forgery and has been deemed mentally incompetent to stand trial in another case.. . . AND ANOTHER YET TO SURFACE? The Los Angeles police are intensifying their search for a second suspect in the O.J. Simpson case, according to an NBC-TV news report, which cited unnamed sources. If true, it represents a change from the prosecution's allegation that Simpson is the only one involved in the murders. The many twists and turns in the case are costing taxpayers plenty: even before the case comes to trial, it has run up a tab of $300,000.