that might have happened when they pulled the motor, doesn't look like much, sometime i think it could be low lives that register on sites like this and look for ppl in there area. anyway most motor pulls are not done in the yard, usually done in a garage. lots of times where the car was found less than 1/4 mile away is where the job was done. plus disgruntled low life employee's of companies where you might by stuff from, i.e. rims, engine mods, ect. if you talk too ppl make up stories about parts being recovered or taged.
last thing was this taken from your driveway? rental property or own? sometimes you can use homeowners insurance to cover.
i have seen ppl on another forum use this ravelco.