What started as an attempted traffic stop came to a deadly end in Volusia County Wednesday when a 17-year-old was killed after he slammed into the back of a parked tractor-trailer as he tried to outrun DeLand officers, according to police.

Callie Keith told WFTV she saw her son, Trevon Lacey, 10 minutes before DeLand police tried to pull him over for not wearing his seat belt near Beresford and Adelle avenues.

"The officer got behind the vehicle, the vehicle began to rapidly accelerate," said Florida Highway Patrol Lt. Robert Asbill.

FHP said the DeLand officer chased Lacey's Ford Expedition briefly, but said when Lacey blew through a stop sign police backed off. When they caught up with Lacey, they said he had already crashed into the parked semi-trailer.

FHP troopers said Lacey was going at least 70 mph when he hit the semi-trailer near the intersection of New Hampshire and Adelle avenues, but Asbill said Lacey may have been going faster.

"On the SUV, the speedometer is somewhere between 80 and 85," said Asbill.

FHP said the impact of the crash caused the semi-trailer to be pushed about 15 feet.

Keith told WFTV her son was on probation and didn't have a driver's license.

"But they had no business chasing my son in a residential area. What if somebody else's child would've gotten killed?" she said.

Lacey was arrested last year on charges of driving without a license, burglary, grand theft with a firearm and armed trespassing.

Lacey still didn't have a driver's license on Wednesday and had a suspended I.D. card, according to FHP.

However, his mother believes the crash could have been prevented.

"I know my son was wrong for driving, I'm not saying he's perfect but they were chasing my son in a residential area. They made my son crash into the back of this vehicle," said Keith.

The SUV Lacey was driving belongs to one of Lacey's family members and investigators are going through it to see if there's any more evidence as to why he sped off.