I watch a movie the other night and I want to know what it was called. It has a cop with a guy it he is trying to get the guy to testify in court and other cops are trying to kill him he steals a bus and he finally gets down to the court to testfiy to the DA

Can somebody help me out

At the moment I can't think of the title, but I do remember that the star was Clint Eastwood.

It could be "16 Blocks" with Bruce Willis and Mos Def.