PHILADELPHIA AP – An assembly line worker was charged with vandalizing a military helicopter at Boeing factory, but federal prosecutors said Tuesday that they were still trying to determine who damaged a second helicopter at the plant.

Matthew Kevin Montgomery, 32, of Trevose, was charged with cutting a bundle of wires on an H-47 Chinook helicopter, U.S. Attorney Patrick Meehan said at a news conference. Montgomery was apparently upset about being reassigned to another line at the suburban Philadelphia plant, Meehan said.