stolen 2012 Blue Nor cross sp

I left my bike inside of an associate of my boyfriends home (Fred). Guy by he name of bobby came over while I wasn't there and said it was his bike so Fred let him take it. I spoke with bobby since then and his story changed to it wasnt his bike it was his uncles bike that was stolen over a year ago and that hed get it back for me as the serial number of his uncles stolen bike does not match my bike, the one he stole from freds. After multiple attempts to get my bike back it is clear he is not doing as he said he would.