The man convicted of killing Bill Cosby’s son asked the trial judge to reopen the case, arguing he was the victim of forged evidence. Six jailhouse letters in which Mikail Markhasev incriminates himself were actually written by a convicted forger, David Gomez, according to Markhasev’s lawyer. In his motion for a new trial, lawyer Henry Hall said Gomez testified in an unrelated murder trial that he forged the Markhasev letters so he could sell them to the National Enquirer for $10,000. “The Markhasev letters, I did those … I’m a dirty bird,” Gomez testified. Markhasev was sentenced in August to life in prison without parole for killing 27-year-old Ennis Cosby in January 1997 while Cosby was changing a flat tire on a dark road. The LA district attorney’s office said Monday it stands by the conviction.