MARSHFIELD — Just a few steps inside the home of Carl and Vicki Mattson, police sent there to check on the married couple on Tuesday encountered a horrific scene.
In a sitting room near an overturned bookshelf, Carl W. Mattson was lying face down with traumatic head injuries, according to a State Police affidavit filed in court. His wife, Vicki, lay a short distance away, evidence of a knife attack clearly visible on her neck.
Vicki L. Mattson would have turned 71 on Wednesday, authorities said. Her husband was 70.
The man who allegedly stabbed and bludgeoned them was identified as Christopher M. Keeley, 27, of Weymouth whom the couple had recently told was no longer welcome as a guest in their Marshfield home, law enforcement officials said Wednesday. Keeley was a friend of a Mattson family member, officials said.
“Keeley was acquainted with the victims,” Plymouth District Attorney Timothy J. Cruz said at a news conference. “This appears to be a targeted attack.”
Keeley remained at large Wednesday afternoon after a 2019 black Jeep Wrangler he had allegedly stolen from the Mattsons’ home was found abandoned in a parking lot in Avon.
Cruz told reporters it was not clear when the couple was killed or how long Keeley had been on the run. But the police affidavit states that Keeley allegedly told a friend on Friday night that he had harmed them.
“Keeley told him that when he was in his old room, in the house in Marshfield, there was an altercation with the older male resident because of the dog barking. Keeley then described an altercation that resulted in Keeley ‘killing them,’ ” State Police wrote in a summary of the friend’s account to investigators. “Keeley did not describe how he killed them, but stated that there is a 1 percent chance they are alive.”
Cruz said Keeley has “mental health issues” but declined to provide more details about his background or what may have motivated the attack. He is known to carry knives and recently dyed his hair red, officials said.
In interviews with investigators, friends and acquaintances described Keeley as a person with mental illness who was recently acting “psychotic.” He was angry and afraid he would end up homeless after a woman who had considered letting him stay with her in Weymouth threw him out on Thanksgiving after he allegedly hit her, police wrote. The Mattsons also wanted him to leave.
While a friend drove him to Marshfield that day, Keeley told him “if [expletive] keeps going this way, I’m going to end up killing somebody,” police wrote in the affidavit. He later said to friends that he was “feeling an urge to hurt people” and specifically wanted to “hurt the old couple he lived with,” police wrote.
The friend contacted police Saturday and asked them to conduct a well-being check on Keeley, according to the affidavit. Officers knocked on the door of the Gotham Hill Drive home, but no one responded, and a Mattson relative told police that Keeley had moved out, the affidavit stated.
The friend called Marshfield police again on Tuesday and provided more details about Keeley’s mental health status and his alarming comments about harming the Mattsons, State Police wrote.
Police returned to the Mattsons’ home Tuesday evening and made the grisly discovery of the slain couple, officials said.
Gotham Hill Drive is a horseshoe-shaped street of single-family homes with mature trees and wide lawns. Resident Dave Kallstrom said he and Carl Mattson attended high school together and that the Mattsons were welcome members of the neighborhood.
“They were good people,” he said. “He’s helped people out in the winter. He’d snow blow your driveway out if you need it, you know?”
Another neighbor shared positive memories of the couple, noting that they were “waiting to retire and go around the country in their RV.”
“There are no words,” the neighbor said. “It’s horrible.”
John R. Ellement can be reached at email@example.com. Follow him on Twitter @JREbosglobe. Emily Sweeney can be reached at firstname.lastname@example.org. Follow her on Twitter @emilysweeney and on Instagram @emilysweeney22.