An admitted terrorist is starting his second week on the witness stand Tuesday in the trial against a Chicago man. David Headley is a key witness in the case against Tahawwur Rana, who’s accused of helping Headley plan terrorist attacks in India and Denmark.

Rana’s defense attorneys say Headley was a master manipulator and even very funny. They say Headley bought funny-looking hats in Copenhagan, Denmark as a sort of souvenir when he was there to scope out the offices of a newspaper that printed cartoons many Muslims found offensive. Headley said he gave those hats to his co-conspirators as a joke. But defense attorneys point out he didn’t give one to Rana. They say Rana wasn’t involved in the Denmark plot and never supported terrorist groups with which Headley was associated.

Prosecutors say Rana never carried a gun, but still played a role in helping move terrorist plots forward.