[visualops]

saw someone in the front row answer a phone call

This and another observation he was "on the phone" when re-entering the theater. However, he wasn't necessarily talking to anyone. He could have faked the call as an excuse to get up or to be ignored (people assume that other people on the phone have a purpose and/or are busy).

[little jeremiah]

I would think that the cops have his cell phone and gotten logs of his calls.