Updated

A Virginia State Police trooper was shot and killed during a traffic stop off Interstate 85 Thursday and a suspect was arrested after exchanging fire with another trooper, authorities said.

State police spokeswoman Corinne Geller said Master Trooper Junius A. Walker, 63, was shot multiple times.

Walker, who was patrolling alone as most troopers do, called for backup after being fired upon just before 1:30 p.m. in southeastern Virginia. The second trooper arrived within two minutes and saw a male suspect firing into Walker's marked police vehicle, which was down an embankment off the southbound lanes of the interstate near the woods, Geller said.

The second trooper fired at the suspect, who fled into the woods. He was found nearby and was arrested before 2 p.m. The suspect was not immediately identified. Charges were pending.

"We're trying to determine if there was a second individual involved," Geller said at a news conference near the scene in Dinwiddie County, just south of Richmond.

Geller said authorities found a weapon and were trying to determine if it was the one used in the shooting.

Gov. Bob McDonnell said Walker was a 35-year veteran of the state police.

"Virginia's public safety professionals are on the front lines every day protecting their fellow citizens from harm and pursuing those individuals whose actions put others in danger," McDonnell said. "These men and women are heroes who place their lives on the line to protect their fellow Virginians."

McDonnell expressed condolences to Walker's wife, two adult daughters and the rest of his family, friends and colleagues.

"Virginia has lost a brave public servant and hero," McDonnell said.

Authorities shut down a section of Interstate 85 near the 45-mile marker where the shooting occurred, and Geller said it likely would be closed for several hours. Southbound traffic was being detoured off at Exit 48.