HARRISON TWP., Montgomery County — A Montgomery County sheriff's deputy said a tree branch caused his firearm to "accidentally discharge" when he was attempting to arrest a robbery suspect Tuesday night.

Deputy John Campbell, assigned to the sheriff's Harrison Twp. division, is on paid administrative leave pending an administrative investigation of the shooting, Chief Deputy Phil Plummer said.

Video footage of the incident was captured by at least one sheriff's cruiser, Plummer said. In it, Campbell is carrying his firearm as he kneels over Ronald Roberts, 41, who is on the ground in a wooded area near Needmore Road and Payne Avenue.

Campbell told sheriff's administrators a "tree branch hit the trigger on the gun, causing the gun to accidentally misfire," Plummer said.

Roberts, of Curundu Avenue in Dayton, was struck in his right hand and taken to a hospital.

Plummer said Campbell said his intention was not to shoot Roberts, who was charged with two counts of aggravated robbery and two counts of felonious assault.

Roberts was trying to flee Campbell and other deputies who were chasing him on foot after the sheriff's office said he robbed an Apex Express truck driver, at the Pacific Pride Commercial Fueling Station, 5445 Webster St., after 8 p.m.

Deputies arrived at the station to find Ronald Saunders in a tractor-trailer, bleeding from his forehead, according to a sheriff's report. Saunders told deputies he had just refueled when a man opened his driver's side door and said, 'let me ask you a question,' " before hitting him in the face with a rock, the report said. The suspect got in and stole a canvas service bag that contained the driver's log book and miscellaneous paperwork.

The driver was taken to a hospital. His condition was unknown late Wednesday.

Deputies also found "a suspected crack pipe" on Roberts after they took him to Grandview Hospital.

Contact this reporter at (937) 225-2414 or kwynn@DaytonDailyNews.com.