JACKSONVILLE, Fla. -

A 16-year-old who pleaded guilty to several charges in connection with a fatal crash last year was sentenced Thursday to 15 years in prison.

Zachary Lambert pleaded guilty in July to vehicular homicide, aggravated fleeing and grand theft auto.

According to court documents, Lambert hit and killed 22-year-old Christopher Thompson (pictured below) near the intersection of Beach Boulevard and San Pablo Road in November.

Prosecutors said Lambert was driving 100 mph as he tried to get away from a Jacksonville police officer and ran a red light, crashing into Thompson's car. The truck Lambert was driving was stolen.

Thompson was leaving his job at Mayo Clinic, heading to catch a ride with his family to Atlanta to celebrate Thanksgiving when he was killed in the crash.

"He loved his family, he loved his friends and he showed that every day," Assistant State Attorney Julie Taylor said of Thompson.

Lambert has a lengthy criminal record and had been in foster care since he was 5.

"This is a child who cannot just be punished," Lambert's defense attorney, Jesse Dreicer, said.

Lambert was facing up to 35 years in prison. Defense attorneys had asked for him to be designated as a "youthful offender" and be sentenced to four years in prison plus two years of probation.

Dreicer begged the judge for mercy on Lambert, saying he needed rehabilitation, not decades behind bars.

Defense attorneys said the teen had a history of mental and emotional problems and had a very rough upbringing, having been abused sexually and physically. Lambert's 18-year-old sister, Jordan Blanton, said her brother could reform.

"I believe Zach can do anything he wants to, and I believe if he puts his mind to it, he can show people that he's not as bad as he seems to be," she said.

Prosecutors, however, pointed to the fact that the boy had been in rehab and in probation several times and continued to break the rules. They painted him as a danger to society.

The judge ultimately came down in between the sentence each side wanted. Lambert will likely be 31 years old when he gets out of prison.

"I'm very disappointed," Taylor said of the sentence. "I think Mr. Lambert has had every opportunity. I can't deny what he's been through has been difficult, but it certainly does not justify his murdering a 22-year-old who was a productive member of our community."

"We were left with a child who I believe the testimony said had great mental health issues and made a horrible decision based off his prior life experiences," Dreicer said.

Lambert's attorneys say while the teen did not take the stand Thursday, he his truly sorry, which they say is evident by the apology letters he wrote to Thompson's family.

The families of Lambert and Thompson declined comment after the sentencing.