As for getting rid of the evidence, the cops definitely won't be able to retrieve any lab equipment or records from that building and the body is likely blown to bits, but you'd be surprised how much DNA you can retrieve from even the smallest bits of bone.



I've seen so many documented cases of arson after a murder in an attempt to get rid of the evidence, but bodies aren't so easily destroyed by flame; granted explosives will certainly destroy most of the body, but the cops only need one piece (given the fact that this building is likely old and secluded, its destruction will certainly indicate something was hidden here and covered up so they will search the wreckage throughly) to potentially ID the victim and assuming he wasn't a loner who kept to himself in his public life, they could investigate people and locations he has been in contact with to hunt them down.