DETROIT – Kwame Kilpatrick was all smiles Monday outside Detroit federal court but he wasn't talking about the government's star witness, Derrick Miller.
Kilpatrick and Miller were best friends at Detroit's Cass Technical High School. The former Detroit mayor was best man in Miller's wedding and the two were side-by-side as Kilpatrick became a state representative and mayor of Detroit. That is what makes Miller such a dangerous witness.
Monday recap: Star witness testifies against former pal Kilpatrick
"It adds an infinite level of credibility to the government's case because of the personal relationship," said legal expert Keith Crobett. "Your best friend, one of your best friends, those are the people that know."
When Kilpatrick was taking cash out of the civic fund for golf clubs, yoga classes and family trips to California. Miller was signing the checks when Kilpatrick was steering state grant money to his wife Carlita and friend Bobby Ferguson.
Read more: Kilpatrick accused of paying for yoga with Civic Fund
Miller was getting the paperwork together to make sure the funds would be delivered. He told the jury Monday that he and Kilpatrick knew the civic fund money was supposed to be for Detroit children and voter education but they agreed no one would ever find out who donated the money or how it was spent.
Miller testified state officials were concerned about Carlita getting money from a grant pushed by her husband, but they did it anyway.
More: Miller's testimony may be vital to prosecution's case against Kilpatrick
His attorney insists Miller's testimony is true.
"Every question that has been put to him, even in court today, he's answered truthfully and thoroughly," said Bryon Pitts, Miller's attorney.
But will the jury believe him?
"They will forgive a witness who has committed bad acts as long as he is frank about that and doesn't try to minimize his own role," said Corbett.
Complete coverage: Kwame Kilpatrick on trial