A teenager fatally shot three people in their Humboldt County home after he was discovered in a girl’s bedroom, the district attorney said in announcing the young man’s guilty plea.

Mauricio Johnson (Sheriff’s office, Tooele County, Utah) 

Mauricio Johnson, 19, pleaded guilty Tuesday to three counts of first-degree murder.

The district attorney’s statement confirmed details about the killings on Feb. 10, 2021, of Margarett Moon, 40; her fiance, Nikki Metcalf, 40; and Moon’s daughter Shelly, 16.

Johnson, who was then 18, entered the home in the Bear River Rancheria, near Fortuna, “with the permission of several of the minors in the home,” the prosecutors’ statement said. He reportedly joined Shelly Moon and some of her cousins. The cousins were sent home in the early hours of Feb. 10, reportedly after Margarett Moon found the teens drinking.

It was shortly afterward that Metcalf discovered Johnson and Shelly Moon in the girl’s bedroom “and began to struggle with” the young man, the statement said. Johnson got a 9mm handgun from his backpack, shot Metcalf, and then shot Margarett and Shelly Moon.

Metcalf and Shelly Moon died at the scene, and Margarett Moon in a hospital.

An earlier affidavit said a panicked Johnson told his brother that he had acted without thinking and “did not want to have any witnesses.” Margarett Moon’s two other children, ages 11 and 13, were unharmed, and one of them called police around 8 a.m. Feb. 10 to report the shootings.

Johnson fled in his mother’s SUV, accompanied by his mother’s boyfriend, Von Eric Keener, 46.  Johnson’s  mother, Melissa, was traveling with them in another vehicle. One of the vehicles had a tracking device, which had been installed by the dealer in case they wanted to repossess it, and the three were located by highway patrol officers on Interstate 80 in Utah around 1:30 a.m. Feb. 11. Melissa Johnson pulled over; the two men kept going, and the highway patrol used a spike strip to stop them.

Mauricio Johnson and Keener were arrested and taken into custody. Melissa Johnson was “briefly detained;” it was not announced that she was accused of a crime.

In addition to pleading guilty to the murders, Mauricio Johnson admitted special allegations for use of a firearm causing death. Under the plea deal, he will be sentenced to 150 years to life in prison, the district attorney said, and his first parole hearing will be in 25 years.

In related news, the Humboldt County sheriff’s department reported last week that Keener had disappeared and was being sought for violation of parole. He had reportedly removed an ankle monitor.

In March, after being returned from Utah, Keener was sentenced to 180 days in jail after admitting to absconding from parole and removing his GPS tracking device.  He was also charged at that time with two counts of failure to register as a sex offender.

Johnson had fought extradition from Utah and was finally returned to Humboldt County on May 16.