Here's a polished version in natural American English:

[Contact me ASAP.]

That was Cedric's reply.

I quickly sent back [Okay,] but something felt... off.

That "as soon as possible" carried this weird urgency. Why the rush?

I tried again: [If it's easier, you can just email me any photos or documents.]

Nothing. Radio silence.

That's how it always went with this cop - guy was like a ghost. Unless he ...