Four teenagers who pleaded guilty to beating a homeless man to death last spring were sentenced to more than 20 years in prison Monday.

The teens pleaded guilty to second-degree murder and conspiracy to commit first-degree murder in the death of Michael Roberts, 53. Authorities said Roberts was beaten, kicked and crushed when his attackers jumped on a log on his chest.

"Very, very few people are capable of committing such a heinous, brutal murder of an innocent person, and when it is done, the people who do that need to be kept away from society," prosecutor Ed Davis said.

Jeffrey Spurgeon, 19, and Chris Scamahorn, 15, were each sentenced to 35 years in prison. Justin Stearns, 18, will serve 27 years, and Warren Messner, 16, was sentenced to nearly 23 years. All four will be on probation for the rest of their lives, court spokeswoman Linda Pruitt said.

Prosecutors had requested life in prison for the four, saying the teens beat Roberts as he begged for his life and then bragged about the killing for weeks before they were caught.

Defense attorneys said the teens had family issues and drug problems.

A fifth youth, Phi Huynk, 16, still faces a charge of aggravated battery.