The head of Exxon Mobil's (XOM.N) shale oil and gas business, a unit involved in merger talks with rival Pioneer Natural Resources (PXD.N), was arrested at a Texas hotel last week on a sexual assault charge, police said.

David Scott, an Exxon senior vice president who oversees all its shale oil and gas production business, was arrested early Thursday morning at a La Quinta Inn & Suites hotel in Magnolia, Texas, the Montgomery Sheriff's Office said.

Efforts to reach Scott were unsuccessful. It was not immediately clear if he had legal representation.