Cop's 'Heart Sank' on Realizing Shots Fired at Minivan Full of Kids

New Mexico officer says he was aiming at the tire.

Jan. 17, 2014— -- A former New Mexico state police officer who fired shots at a minivan during a chaotic traffic stop last year had no idea the vehicle was full of children and his "heart sank" when he finally realized it, he told ABC News in an exclusive interview.

Elias Montoya, 53, was terminated in December after he fired three shots at the vehicle carrying a mother and her five children ranging in ages from 6 and 16. Montoya fired the shots after a routine traffic stop evolved into an intense encounter that included a high-speed chase.

"My heart sank when they finally stopped and I was at the passenger side at that time seeing them get out at gunpoint again," he said. "I couldn't believe it that there were that many children in there."

VIDEO: Minivan Stop Turns to Wild Chase for Mom, Kids

Video from a police cruiser's dashboard camera taken during the Oct. 28 traffic stop showed Montoya shooting at the minivan three times in Taos, N.M. The video garnered national attention.

Montoya says it was the first time he had fired his gun on duty during his 12 years as a state cop. At the time, Montoya said, he didn't know the majority of the people inside the vehicle were children.

New Mexico State Police will not comment on Montoya's termination, but say he violated the department's policy regarding the use of deadly force.

The incident began when motorist Oriana Farrell, 39, of Memphis, Tenn., fled from an officer who initially pulled her over for speeding, according to police. That same officer caught up to Farrell and pulled her over a second time, according to dash-cam video, and that's when things escalated.

During the second stop, Farrell refused to get out of the van. She eventually agreed to exit, but jumped back into the driver's seat as an officer tried to restrain her.

Her son, 14, confronted the officer and a scuffle ensued. The boy eventually ran back into the minivan after the officer aimed a Taser.

As back-up arrived, which included Montoya, Farrell and her family locked themselves inside the minivan. An officer broke the vehicle's back windows with a baton as the children screamed in the backseat.

Montoya, a father of three, says dispatch only told him to respond to an unruly driver on a highway near Taos.

"I'm approaching the van on the left-hand side," he said. "All I see is silhouettes of heads. A bunch of silhouettes of heads and what went through my mind is that we're outnumbered."

He says the minivan's tinted windows prevented him from seeing who was inside. When the driver started to flee for the second time, he lined up with the white line in the road and shot at the tire to immobilize the minivan.

"I'm not shooting at a human being. I'm shooting at a tire," Montoya said.

Montoya missed the tire as Farrell took off down the highway. After a chase that reached speeds of nearly 100 mph, Farrell and her teenage son were arrested in front of a Taos hotel.

Farrell was later released on bond and faces charges of child abuse, fleeing and misdemeanor possession of drug paraphernalia for a pair of marijuana pipes that authorities say were in the van. Farrell has since said she was protecting her children.

Montoya later bought the entire family food from McDonald's during the booking process, according to a police report.

"If I knew that there was even one child in that vehicle," he said, "I wouldn't have done it."