Who is Sheriff Risley from The Ox-Bow Incident and what is their importance?

The county sheriff is Sheriff Risley. When word of Kincaid's murder comes to Canby's, Davies sends his employee and Art Croft to find Sheriff Risley with the hope that he will be able to talk the growing mob down. However, Sheriff Risley is already out at Drew's, perhaps already investigating the attack on Kincaid. For this reason, the mob continues with their plans rather than wait for the sheriff. In the end, the sheriff realizes what the men have done, but he decides to do nothing about it despite Judge Tyler's urging that the entire mob be arrested.