Just curious, why would one of the neighbors know him..
I mean.. if he is a private investigator wouldn't the NOT know him?
Exactly, they wouldn't, but by your simply being concerned because you see this stranger, 'waiting for someone' and you asking them if they 'know him'. Get it? You need plausible deniability and they need a heads up. If this is local LEO and you break up a covert they are gonna be pissed. Then when, of course, no one knows him you call LEO to ask them who this is. You need to act dumb as a rock and concerned. You know, new mother and all just worried.... big bad looking guy blah blah.....
Insurance is getting very heavily into PI's who then wreck people who have legitimately been hurt on the job because they catch them picking up a toddler or some such shit. So yeah I'd shit on his 'stake out'. Another reason I'd shit on it is pure disgust at his doing a bad job. You should not see him if he's doing it right. So report his stupid popo or faux popo ass.