[T.B. Yoits]

It’s far more believable than someone having a device hidden in there for four months.

[The Louiswu]

"... having a device hidden in there for four months."

Have you ever heard of people doing renovation to their homes, demoing a wall or ceiling and finding all manner of weird stuff?

I did some work on a previous home and in the crawl space I found an old plastic skeleton laying in the dirt, would have stayed down there forever unless I decided to do a few improvements under the house.

I can see someone walling in some explosives or in a ceiling, how they ignite it I don't know, but it's possible.