BROKEN ARROW, Oklahoma - Investigators are working to figure out how a fire started March 18 at the former Bever family home in Broken Arrow.

The fire destroyed the house where prosecutors say Robert and Michael Bever stabbed their parents and three of their siblings to death in 2015. 

Robert Bever is in prison for the rest of his life after pleading guilty. 

His younger brother, Michael Bever, is scheduled to stand trial this summer.

Neighbors said they're used to people stopping by to look at the house - and even vandalize it.  

"They try to take things - pieces of wood from the side and stuff like that ya know," said neighbor Pat McGaha. 

There's no word yet how this will change the plans for the site to be turned into a memorial garden.