A 33-year-old New York City Department of Environmental Protection employee was shot and killed by a co-worker early Monday morning. Aron J. Thomas of Olivebridge, N.Y. was shot at around 6:45 a.m in a NYC DEP building in Kingston, N.Y., where he worked as a a watershed maintainer.

Police have arrested fellow employee David Reese, 53, who they allege murdered Thomas. They have also recovered the alleged murder weapon. Officials say the shooting was the result of "a personal dispute" between the two men. Thomas had worked at the facility for nine years and was part of a team that maintained the quality of New York City's upstate reservoirs.

“We are shocked and saddened by the senseless act of violence that occurred early this morning at DEP’s offices in Kingston, N.Y. The thoughts and prayers of all DEP employees are with the victim’s family and loved ones," DEP commissioner Carter Strickland said in a statement today.

Reese is expected to be charged with the murder later today.