next Image 1 of 2

prev Image 2 of 2

A 15-year-old was sentenced to 85 years in prison for killing and sexually assaulting his teacher at a Maryland youth facility, MyFoxDC reported.

Brian Wonsom pleaded guilty on Friday to killing his teacher Hannah Wheeling with a cinder block when he was 13.

"It's a tremendous tragedy," Prince George's County State's Attorney Angela Alsobrooks said. "And there’s no answer for why a 13-year-old boy is capable, would be capable, of killing and raping in the manner that he did, but we are now satisfied that we have removed the threat from our community. It is sad on so many levels.”

Court records show that Wonsom also pleaded guilty to a second violent attack that originally was not made public.

Wonsom was being held at Cheltenham Youth Facility, which serves youth awaiting trial or court disposition, after his mother found stolen items in his possession.

Wheeling’s bloody body was found outside a cottage on February 18, 2010. Additional evidence, including a bloody sweatshirt with matching DNA to the victim, was found by state police investigators under a stairwell. The name inside the sweatshirt read “Brian Wonsom, ” the report said.

DNA matching Wonsom was found on a lanyard that was used in the attack.

Teen Sentenced 85 Years For Killing Teacher at Maryland Youth Facility: MyFoxDC.com

Prosecutors believe Wonsom is a sociopath who would need decades of intensive therapy before anyone would think it was prudent to allow him to walk the streets again, the report said.

In court Friday, prosecutors showed evidence of the teen trying to kill another woman before attacking his teacher at the facility in 2010. The boy is also a prime suspect in an attempted murder case.

Prosecutors say the 13-year-old entered a woman's apartment through an unlocked sliding glass door and stabbed her several times before she screamed and he ran off. Investigators connected Wonsom to the crime through fingerprints found on a knife, MyFoxDC reported.

Prosecutors say doctors who examined the teen found him to be sane, but wicked.

"Oh yeah, completely without being mentally ill,” Prosecutor Wes Adams said. "He exhibited no remorse, childhood onset anti-social personality disorder. That's not criminally insane, that's dangerous.”

Why he chose to attack Wheeling is still unclear.

Since there is parole in Maryland, Wonsom will be eligible to apply in his mid-to-late 50s.

Click here to read more on this story from MyFoxDC.