[Alberta's Child]

The police could get his phone records directly from the phone company. They only requested them from him to see how he'd respond. His response makes him appear like he is hiding something ... which is what the police suspected.

There's a 3rd possibility for why he redacted the phone records. The assault may have been a gay lovers quarrel, and he's trying to hide the identity of his attacker.

[dfwgator]

Where are Dr. Johnny Fever’s “Phone Cops”.....

Johnny: [after hearing the sirens] It’s the phone cops. They know what I did here today.
Venus: What are you talking about?
Johnny: They’re coming to get me, man!
Venus: That’s paranoia, man!
Johnny: Wake up, sucker, this is the phone company we’re talking about! They see everything, they know everything, they got their own covert police force! I’m probably wired for sound right now! I gotta get out of here!
Venus: Johnny!
Johnny: Don’t use my name!!