Mob uses the dump to send a message. They've used the dumps on numerous occasions. It's their MO.
If it had been the government. They would have just picked him up with a nondescript car, put him in a plane and dropped him somewhere over the ocean....Never to be seen again.
This video has some interior shots of the Marini house...
http://abclocal.go.com/wpvi/story?section=news/crime&id=7883768
I don’t see any tools, but there are some pieces of wood and pipe laying around.