workers in mississippi is in jail charged with raping another employee. and now a cnn investigation uncovers his criminal history and raises questions whether this entire incident could have been prevented by doing a simple background check. special investigations unit correspondent abby boudreau goes looking for answers from bp and the company that did the hiring. >> reporter: one of the thousands of cleanup workers who descended on the gulf coast was this man. rundy charles robertson. he was in charge of numerous workers on this now deserted mississippi beach. the problem was all of these people coming to town were strangers and the residents here had no idea who they were or where they were coming from. and apparently they had good reason to be concerned. robertson was a convicted sex offender. and he was breaking the law by not telling local law enforcement where he's living. >> i don't understand how they could have had a man like that as our supervisor. >> do you think what happened to