MONTEREY COUNTY (KRON/BCN) — A teen has pleaded guilty to stabbing his grandparents and a Soledad police sergeant last year, according to Monterey County

prosecutors.

18-year-old Robert Bagwell, entered a guilty plea to charges of attempted murder of a police officer and two counts of elder abuse in exchange for a sentence of 18 years and four months in prison.

Investigators said on May 19, 2014 police responded to a home on Second Street in Soledad after someone called 911 and hung up.

Upon arrival, Sgt. Thomas Marchese heard loud, distressed voices coming from inside the home. He knocked on the locked door and then tried to open the door. He eventually drew his gun and forced it open, prosecutors said.

Investigators said once Sgt. Marchese got inside, the suspect was found on top of his grandfather, apparently beating him. Marchese holstered his gun and tried to stop Bagwell, but the teen was armed with a four-inch paring knife and attacked the sergeant, saying, “I am going to kill you,” prosecutors said.

Marchese was stabbed seven times, but his Kevlar vest prevented Bagwell from stabbing him in the chest. Marchese suffered wounds to his neck and arms and was treated in intensive care, prosecutors said.

Bagwell’s grandparents both suffered multiple stab wounds and were hospitalized for weeks after the attack.

A sentencing hearing for Bagwell is scheduled for June 24.