Prosecutors charged two men Friday in connection with a collision on Alcova reservoir this summer that killed an 11-year-old boy.

The charges come roughly two months after the death of Brenton McCullar of Evansville when the Yamaha personal watercraft he was driving collided with a 25-foot speed boat.

Mark Blackett, who is suspected of driving the boat, is accused of negligent vehicular homicide, a misdemeanor. Stephen Koch, who was allegedly riding the watercraft with McCullar, faces a charge of child endangerment.

Blackett, 38, and Koch, 30, each face a year in jail if convicted. Both men pleaded not guilty to the charges Friday during brief appearances in Natrona County Circuit Court.

A judge set bond for both men at $1,500.

The court did not release charging documents that described allegations against the men, nor did authorities detail the circumstances of the Aug. 30 crash immediately after it happened.

The Natrona County Sheriff's Office and Wyoming Game and Fish investigated the cause of the collision, then forwarded their work to the Natrona County District Attorney's Office.

Neither the boat nor the personal watercraft sunk after the crash. The boy was wearing a life vest at the time of the crash.

Reach crime reporter Joshua Wolfson at (307) 266-0582 or at josh.wolfson@trib.com.