DETROIT - Two thrill-seeking teenagers stabbed an adult acquaintance, took a blowtorch to his corpse and threw his severed head into a river, prosecutors said Monday as they charged the pair. Jacob Orlewicz, 17, and Alexander James Letkemann, 18, ambushed 26-year-old Daniel Sorenson last Wednesday in a garage owned by Orlewicz’s grandfather, Wayne County Prosecutor Kym Worthy said. A tarp had been spread on the floor, she said.

“They lured him in the garage where they prepared a space to kill him,” Worthy said at a news conference.

Sorenson, who had worked as a bouncer, was stabbed multiple times in the back, his head was sawed off and his body was wrapped in the tarp, authorities said. Orlewicz and Letkemann burned his hands and feet with a blowtorch, possibly in an effort to conceal his identity, Worthy said. The teens loaded Sorenson’s torso in a pickup truck, dumped it in a cul-de-sac and set it on fire using gasoline. A utility crew found it Thursday morning, police said.

Sorenson’s head was found Saturday in the Rouge River. Sorenson’s history as a registered sex offender in Michigan and Illinois and the fact that he may have owed his attackers a small amount of money appear to have had nothing to do with his death, Worthy said.