I will reiterate this because I think it got lost. I checked the Kandiyohi county police scanners, the Willmar police scanner, and the local state police scanner for the morning, and got nothing. It wasn't a 911 call, and it wasn't a traffic stop. I think this also rules out a wellness check - several wellness checks happened between 7:00 am and 11:00 am in Kandiyohi county, and none went to Nick's door.
It might have been a CPS call or some other state agency with arrest powers that brought him in - I am actually leaning in that direction. It could also have been the ATF or FBI or some federal garbage too, given how they show up at the doors of random gun owners and republicans.
It would have been well within Aaron Imholte's pettiness to call CPS on the Rekietas.