Truck driver Ron Lantz told CBS News he recognized the suspects' Chevrolet Caprice parked at the rest stop from descriptions that had been broadcast all Thursday evening over trucking channels.
"I had no doubt because I'd been listening to the radio," he said. "I was listening to (Montgomery County Police Chief) Charlie Moose on there describe the car and license plate number."
In an interview on The Early Show Friday morning, Lantz said that he called 911 from the rest stop and that authorities then asked him to block the exit of the rest stop until they could arrive. Lantz said he and another trucker pulled their rigs across the exit lane.
"It wasn't about 15 minutes at the most, and they were there, the Frederick County police were there first," he said.
It was a long 15 minutes, he admitted, but added that he wasn't scared. Told by interviewer Julie Chen that his life could have been in danger, he said, "That's what my wife said but I didn't pay attention to that."
Authorities surrounded the Chevrolet and arrested the two men inside. Lantz said he did not see the arrest since he was at the exit, too far away to see what was going on by the Caprice.
"I wasn't that close to seeing them taking them out of the car," he said. "I could see what the police were doing with their guns drawn. They just swarmed in like a bunch of birds, you know, and all the lights are gone. Everybody couldn't figure out what was going on."
Forty-two-year-old John Allen Muhammad and 17-year-old John Lee Malvo were taken into custody for questioning in the three-week reign of terror that paralyzed the greater Washington, D.C. area. Authorities have since confirmed that a rifle found in the car matched the one used in many of the 14 sniper shootings.
Lantz said he had been on the road since 11 p.m. Wednesday when he left Wilmington, Del., and pulled into the rest area at the little town called Margot, between Baltimore and Hagerstown, a little after 1 a.m. Thursday.
In earlier interviews, Lancz also denied being a hero and said he just wants "people to think that what I did was what I should have done."
Lantz may be eligible for a reward, which could total $500,000.
"If I had the money - which I don't care whether I get the money or not - it would probably go back to the families of the victims, the families of the people whose lives were taken," he said Friday.