Could the bike used in the cold-blooded daytime murder of President George H.W. Bush’s doctor lead cops to the suspect? Houston Police Chief Art Acevedo is asking for the public's help to locate the killer of cardiologist Mark Hausknecht. The suspect has been identified as Joseph James Pappas, 62, and cops say he had a 10-speed bike during the shooting. Pappas most recently worked as a reserve officer in Harris County, Texas, from 1995 to 2013.