Damaso Lopez Serrano also known as "The Mini Lic" and Cooperating Witness 1 in United States v. Jesus Raul Beltran Leon can't be found on the BOP Inmate Locator probably because they keep having to move him across the country to keep him from getting taken out for testifying against Beltran Leon. Beltran Leon is allegedly part of Juan "El Chapo" Guzman's allegedly unlawful business and Serrano is a snitch listed as the first cooperating witness in the case against Beltran Leon.
Serrano was locked up at MCC Chicago last year until he was moved to MCC New York for his own protection only to be moved again for the same reason. The feds really care about their snitches while they need them to testify so Guzman's organization probably will not get to him until after the case is resolved. Then he will probably be moved from SHU to PC yard to SHU to another PC yard again and again until someone finally gets to him. The BOP will inevitably send him to a yard where he is not safe and when he checks in (requests protective custody) eventually he will be celled up with someone that will do something to him and nobody will care.