CHARLESTON, W.Va. -- The man accused of killing a West Virginia sheriff bought several guns -- not just one -- after he had been determined legally ineligible to own them, a prosecutor said Friday.Michael Sparks said the purchases were made after February 2010, when 37-year-old Tennis Melvin Maynard was deemed ineligible. Sparks, the Mingo County prosecutor, has refused to say why Maynard isn't allowed to own a gun, but the suspect's father has said Maynard has mental problems and previously had been institutionalized.Since 1968, federal law has banned certain individuals with a history of mental illness from buying guns. The nationwide background-check system, which also is used to prevent convicted felons from buying guns, was established under the 1993 Brady Bill.A West Virginia database that forwards information on people involuntarily committed to a mental institution to the national system became operational in January 2011. Sparks said Maynard's "multiple" purchases were made before then, including the weapon allegedly used to shoot Sheriff Eugene Crum as the lawman ate lunch April 3 in a Williamson parking lot.Sparks said that gun was purchased in Logan County.Although Sparks wouldn't go into specifics, he said video surveillance -- none of it close to the crime scene -- is being collected as part of the investigation."One of my primary goals is to get as much video, any camera evidence to give a timeline on where [Maynard] was and what he was doing," the prosecutor said.Maynard was shot and wounded by a Mingo County deputy in a chase after the attack on Crum. The West Virginia State Police said he crashed his car into a bridge in his hometown of Delbarton, then got out and pointed a weapon at the deputy, who then shot Maynard.The State Police has said Maynard is up and moving at a Huntington hospital. Authorities have charged him with first-degree murder and attempted murder. Additionally, federal prosecutors are investigating Maynard to see if he lied on his gun permit application.After his public defender cited a conflict, Huntington attorney Rick Weston was appointed to determine if Maynard wants to hire his own counsel or wants one appointed for him, Sparks said.