NAMPA (AP) - A Nampa woman who was reported missing was killed by her boyfriend with a hammer, stuffed into a trunk and then buried in a cornfield with the help of three other men, according to police.

The boyfriend, Alfredo M. Martinez, 39, has been arrested on an unrelated parole violation but prosecutors have not charged him in the death of Selena Dawn Thomas, 37.

Prosecutors, however, charged three other people with crimes Thursday, including aiding and abetting murder and failure to notify authorities of a death. In court documents filed in those cases, police contend that Martinez told them he struck his girlfriend in the head with a blue hammer and then buried her body.

Police said they haven't found Thomas' body.

Martinez's Idaho arrest record includes aggravated assault and aggravated battery convictions.

In 2010, Martinez walked away from his assigned work at the South Idaho Correctional Institution Community Work Center south of Boise. He was caught 13 hours later.

Thomas was reported missing Monday and was last seen Aug. 14.