Longarm and the Diamondback widow

Sheriff Des Rainey was a good lawman, just doing his job, returning from a ranch left in charred ruins after giving the murdered corpses left behind a decent burial. But someone got the drop on him as he was stepping into his own jailhouse--and a shotgun blast blew him clear back out into the muddy main street of Diamondback. Rainey was a good friend of Marshal Billy Vail. They had served as Texas Rangers together. So Billy sent his best deputy marshal to find the killer made Mrs. Rainey a widow. But when Longarm rides into Diamondback, no one is talking--except the young beautiful widow herself, who will do anything to get Longarm to find her husband's killer.