The man who fatally stabbed and beat a 24-year-old stranger on a Washington, D.C. Metro train in 2015 has been sentenced to 35 years in prison.

Jasper Spires received the sentence of prison time plus five years of probation on Friday afternoon for the murder that stunned the city. A plea deal allowed him to avoid a life sentence.

Spires killed Kevin Sutherland on board a Red Line Metro train on July 4, 2015, stabbing him dozens of times after trying to steal his phone.

Sutherland's mother, Theresa Sutherland, said she believed justice had been served.

"The fact that he finally did accept responsibility for what he did, we felt that the 35 then was justified," she said.

Sutherland's father, Douglas Sutherland, expressed compassion for Spires and his family.

"There was nothing but sadness in the court. I feel deep sadness for him. I feel deep sadness for his family. He took one life and he destroyed his own," he said.

Spires' lawyer said he was mentally ill and had begun to hear voices at the time of the crime, when he was 18. Spires apologized and read a brief statement. His lawyer said Spires said several times he wished he could take Sutherland's place.

Sutherland was on his way to a 4th of July party when Spires attacked him. He got on the train at the Rhode Island Metro station and was attacked before the train reached the next station.

Prosecutors said Spires attacked Sutherland at random.

Metro surveillance video showed what happened before the stabbing.

Spires was standing near the fare machines at the Rhode Island Avenue Metro station about 12:40 p.m. when Sutherland walked through the turnstiles, officials said. Sutherland went up the escalator, walked to the front of the platform and waited for a downtown-bound train.

Spires went up to the platform a short while later, officials said. As he stepped off the escalator, he put on gloves. He then walked toward the front of the platform and waited for the same downtown-bound train, officials said.

Both men boarded the second car of the train. Sutherland sat down in the middle of the car.

The train was en route to the next station, NoMa-Galludet, when Spires snatched Sutherland's phone from his hand. Spires then attacked his victim with a knife, officials said.

According to officials, Spires stabbed Sutherland in the abdomen, back, sides and arms repeatedly. Sutherland fell on the floor, and Spires continued to stab him. Officials say Spires also kicked Sutherland in the body and head.

As the attack concluded, Spires threw the cell phone at Sutherland, hitting him in the head.

Spires also threatened one witness who tried to notify the train operator, telling them to "shut up" while brandishing the knife, officials said.

He robbed and threatened two other people on the train, including one senior citizen, News4 reported.

When the train arrived at the NoMa-Galludet station, Spires began to flee. Officials said he ran down the stairs and threw the bloody knife in a trash can.

Spires dropped his backpack while hopping over the turnstiles at the station. He turned around, but ultimately continued to run away without it, officials said.

Witnesses waited with Sutherland as his attacker fled. Metro employees and fellow passengers called 911, but Sutherland was unresponsive when first responders arrived, officials said. He was pronounced dead at the scene.

Sutherland, who had interned for U.S. Rep. Jim Himes, was stabbed 19 times and cut 16 times, police said. Several of the stab wounds were deep enough to damage his internal organs.

Spires was arrested two days later.

Spires, who attended Louisburg College in North Carolina, was admitted to psychiatric facilities at least two times in the three months before the attack, The Washington Post reported. He displayed "bizarre and combative behavior" at one facility and needed to be restrained, the Post reported.

"Yes, my client has mental problems, but he is innocent of these charges," Spires' lawyer, Antoini Jones said during a court hearing last year, the Post reported. "D.C. police need to catch the real killer. No one identified my client as the killer."

A grand jury indicted Spires in 2016 on charges of first-degree murder while armed (premeditated and felony murder) with aggravating circumstances, assault with a dangerous weapon, armed robbery of a senior citizen, armed robbery, and carrying a weapon outside a home or business.

Spires' lawyer requested that he serve his time in a Bureau of Prisons medical facility. The judge said she cannot order that but will suggest it.

But nothing will bring Sutherland back.

"I miss my son every day," his father said outside the courthouse.