A suspect police described as “mentally disturbed” attacked a man in Arlington County last week and tried to stab him with a pen, according to police.

Police said Zachary Thomas, 23, was milling about the 4200 block of N. Fairfax Drive the morning of Sept. 19 when he approached a man walking to work. Thomas was mumbling and attempted to block the man’s path along the sidewalk, according to Arlington County police spokesman Dustin Sternbeck.