A Lancaster teenager will serve at least 54 years in prison for robbing and killing a local elementary school teacher during a home invasion in Lancaster city in 2014.

Marcus Rutter, a 17-year-old charged as an adult due to the nature of the crimes, pleaded guilty earlier this month to first-degree murder and related counts regarding the December 15, 2014, killing of Nicole Mathewson.

On Friday, Lancaster County Judge David Ashworth ordered Rutter serve 54 to 109 years in state prison.

Juveniles convicted of first-degree murder no longer face mandatory life sentences, in accordance with a U.S Supreme Court ruling that deemed such mandatory sentences “unconstitutional.”

Rutter is the first juvenile to be sentenced in Lancaster County under such circumstances since that ruling.

Judge Ashworth called Rutter "irretrievably depraved” and that it was “improbable” he would change in time.

The judge noted that Rutter has never apologized to the Mathewson family. Rutter read from a written statement, saying he didn’t like the person he became.

Mathewson, a 32-year-old teacher at Brownstown Elementary School, was slain in the middle of the night inside 701 North Franklin St.

Mathewson was beaten to death inside the house. Her debit card, vehicle and other items were stolen.

Mathewson’s parents, along with other relatives and friends, spoke in court Friday.

Tina Mathewson, Nicole’s mother, said her daughter’s “legend will live on forever.”

Mark Mathewson, Nicole’s father, asked Rutter, “Was it worth it?”

In all, Rutter pleaded guilty to: first-degree murder, conspiracy to first-degree murder, burglary, robbery, receiving stolen property, access device fraud.

Thomas Moore, a 26-year-old co-defendant, also pleaded guilty and is serving a life sentence plus 20 years.

Rutter’s defense team argued that Moore was the leader and influenced Rutter to go along for the burglary because he was scared of Moore.

Not true, First Assistant District Attorney Christopher P. Larsen countered.

Larsen said Rutter’s behavior and phone calls after the killing showed he had no remorse.

Rutter even stole a container of Christmas cookies that Nicole baked and he ate them after killing her, Larsen said.

Larsen disclosed several other things Rutter did and said around the time of the murder, including:

- He had been watching Mathewson's house and suggested it as the home-invasion target.

- While keeping Mathwewson captive, bound and gagged, Rutter used her phone to access Facebook.

- Rutter "liked," on Facebook, a news story posted about the murder.

- Rutter tried to have the money stolen in the robbery placed into his prison account after he was arrested.

Judge Ashworth called Rutter an “active co-conspirator.”

Police learned that Rutter had some of the stolen items and that a withdrawal was made from Mathewson’s account soon after the break-in, according to charging documents.

Lancaster city police Detective Jimmy Mummau filed charges.

MEDIA CONTACT: Brett A. Hambright, 717-295-2041; bhambright@co.lancaster.pa.us; Twitter: @BrettHambright