Check social media.
I'd also check calendar to make sure they didn't take vacation.
I'd also check places they frequent, someone had to have seen them or noticed.
There's a dude in my apartment complex who starts his loud ass fucking beater truck at like 5 AM.
Pisses me the fuck off.
Seriously, it's awful. I want to put sugar and flour in his gas tank just to get his car to shut the fuck up.