Two juvenile boot-camp inmates allegedly used a pickax to kill a camp counselor, rolled his body into a lake, then stole his car in an attempted escape.

Jermaine Jones, 16, and Mazer Jean, 17, were arrested a half-hour after the Tuesday attack and accused of murdering Mike Sierra, 40. Investigators said Jean has admitted that he watched Jones hit Sierra several times Tuesday.After rolling his body into a lake, the teens took Sierra's Hyundai and drove off, authorities said. Collier County deputies arrested them following a chase that reached speeds of 95 mph.

Sierra was supervising Jones, Jean and a third inmate while the trio cleared woods by the Big Cypress Wilderness Institute, 30 miles east of Naples, said camp spokeswoman Magie Valdes. The camp has no fences and staffers aren't armed.

Jean and Jones had been at the camp less than four months.

In addition to first-degree murder, both were charged with escape, grand theft auto and aggravated fleeing and eluding.