Claiming an investigation so early is a crapshoot if they were scum. Its pretty much guaranteed we'd have the standard roles in this game (cop, doc, RB, etc) so with an early cop claim for night 1, and the fact that P7 targeted me and said I was town has me thinking they're town. Doesn't make sense for scum to do this so early in the day (or before everyone else posted) and to try to buddy with a townie when it could so easily back-fire, and after only 1 vote on them. I'm not 100% sold they're town, but leaning that way currently, enough so that I can feel confident looking elsewhere today.
Sounds reasonable, but again, I'm wary that they could just as easily be scum. Tristan said the PRs change daily, so it's not like someone is permanently a cop. It's a 1/8 chance (maybe closer to 1/4 since I doubt there's only one mafia in this game) that the scum team got the role last night. As such, I don't see an investigation as 100% confirming their alignment or yours. They could be scum lying or telling the truth, and trying to play to town favor in either scenario.