A father and son on the run from police after tying up five women in a Utah basement abducted and killed a rail line worker, Wyoming prosecutors said Tuesday.

The Lincoln County Attorney's Office charged Flint Wayne Harrison and his son, Dereck James "DJ" Harrison, with first-degree murder and kidnapping in the death of Kay Porter Ricks, 63. An autopsy determined that Ricks died of blows to the head, a police statement said.

Ricks vanished during his May 12 shift maintaining Salt Lake City's light rail system, a few miles from the home where the Harrisons hid out during a police manhunt, investigators say.

The body of the Mormon grandfather was found later in Wyoming, along the route the Harrisons likely took to flee Utah, police say. An FBI agent discovered Ricks' Utah Transit Authority truck near the suspects' hideout in the western Wyoming backcountry.

The Harrisons were arrested May 14 after a dayslong search. The father turned himself in and helped lead police to their makeshift campsite. Dereck Harrison, 22, was spotted near a roadblock that night and taken into custody.

They were sent back to Utah to face 16 charges each, including kidnapping and drug possession, in connection with allegations they held a mother and her four teenage daughters captive. The younger Harrison was a close friend of the woman's family.

The men were using drugs heavily on May 10 when they lured the family to Dereck Harrison's house in Centerville, outside Salt Lake City, police said. Instead of the barbecue the Harrisons promised, they restrained the women with zip ties and beat the mother with a baseball bat because they falsely believed she had reported them to authorities, according to charging documents.

The family managed to break free and escape, but the men fled. Police say they ditched their car and got a ride to Salt Lake City, where they spent a night in a hotel and another night with a friend before making their way 250 miles north to the Pinedale, Wyoming, area where Flint Harrison lives.

Police believe the Harrisons left Salt Lake City on May 12, the same day that Ricks disappeared. Surveillance cameras captured video of his truck that night in Wyoming, not far from where his body later was found.

Ricks was a handyman who lived by a regimented daily routine and helped neighbors fix their lights and ceiling fans during his free time. The day he vanished, Ricks turned around after leaving for work because he realized he forgot to kiss his wife of 42 years, a family spokesman has said.