Maryland authorities say they've charged a New Jersey police officer after an alleged road rage incident in which one person was fatally shot.

Joseph Walker (WBAL TV)

Maryland State Police responded Saturday evening to a shooting on the shoulder of the ramp from northbound Route 3 to Interstate 97 near Millersville.

Troopers say they were told that a road rage incident had happened between the two vehicles before they pulled over and the shooting occurred.

Troopers believe the driver of a minivan, 40-year-old Joseph Walker of Easthampton shot the driver of a Honda, 36-year-old Joseph Harvey Jr. of Millersville, after Harvey approached the minivan. Harvey later died.

Harvey appraoched Walker's car in an "aggressive manner" according to WPVI TV prompting Walker to fire at him.

Troopers charged Walker on Sunday with second degree murder and manslaughter. He is a sworn officer with the Hudson County Prosecutor's Office in New Jersey.

"We are aware of the fatal shooting incident involving one of our detectives, who was off-duty and traveling in Maryland with his wife and children," Hudson County Prosecutor's Office spokesman Gene Rubino said today in a statement according to the Star Ledger.. "All press inquiries regarding this matter are being referred to Maryland law enforcement authorities, who are conducting this investigation."

Walker's neighbors were in disbelief upon hearing of his arrest. "I'm overwhelmed. I can't believe this. He's a great guy, great neighbor, great man, great father. We golf together, I'm in disbelief right now," neighbor Tom Mills told WPVI TV.

They say Walker has a wife and three children who were inside the van at the time according to WPVI TV. He is being held on $1million bail.

The Associated Press contributed to this story