NAMPA, Idaho -

A southwest man police say killed his girlfriend by hitting her in the head with a hammer and then buried her body in a cornfield has been charged with second-degree murder.

Authorities on Thursday also charged 38-year-old Alfredo M. Martinez of Nampa with destroying evidence and failure to notify authorities of a death.

Police found the body of 36-year-old Selena Dawn Thomas Aug. 21 and a coroner determined she died of blunt force trauma to the head.

Court records say Martinez told officers he hit her in the head with a hammer and then pushed her and caused her to hit her head on a dresser.

Court records say he also told investigators he buried her in the cornfield with the help of three other men.