Hector Pablo Molina, 58, was arrested Monday afternoon, about 45 minutes after the slaying and booked on suspicion of murder, according to police.
The name of the dead man, believed to be 55, was not immediately available. He was found near the 2800 block of Main Street shortly after 3:30 p.m., Lt. Scott Arsenault said.
A witness told officers the assailant fled in a red pickup and wrote the license number in some roadside dirt, police said.
The truck was traced to a home in the 2100 block of Clairton Place, where Molina was watched and arrested as soon he got into the pickup, police said.
The victim lived in a van and apparently looked after the farmland where he was slain, according to Arsenault.
Molina was denied bail pending arraignment, which is set for Wednesday afternoon.