If they have him dead to rights on the breach, they probably wouldn't need motive for probable cause to investigate. If you walked out of a bank carrying a big bag of money while wearing a ski mask I'm sure the police won't bother over why you want the money so badly before investigating.

I would think a prosecutor could still use it in the trial if planned properly. Might as well prepare because I would guess the defense would try to use the old "they deserved it!" defense.