"Accidently" That is the story he is sticking with?
As far as leaving the roaches outside, I had put them outside just because I was getting tired of having them in the house. I figured the kids would notice and drag the bin back inside at some point. A week or more passed, however, and then we had a cold snap. By then, I guess, everyone had had enough of the vermin.
A few years later, after moving to another house, we found an ex-cockroach inside an old sofa. This was Bertha (as big as her name), who had gone missing before her siblings met their demise.