Mother Buys Used Stroller For Her Daughter, But When She Finds This Inside It She Calls The Cops

Parked Van

And the cops were right, because the same night, at 01:22, Mindy and Laura saw a van parked in front of the house. It was a perfectly normal postal delivery van, so it was obvious that the thieves worked there. Makes sense because they were the only people who had gotten their hands on the stroller after Laura sold it to Mindy.