Family members of the Plymouth man accused of a fatal stabbing at their home this week told police they noticed a “recent decline” in the defendant’s mental health, hinting that he looked forward to his father’s death.

Matthew Paluzzi, 26, is being held without bail and is set to see a forensic psychologist after he allegedly stabbed his 73-year-old father, Anthony Paluzzi, to death at their home early Thursday.

The defendant’s mother, Wendy Paluzzi, told police that her son’s mental health “spiraled” after a previous criminal case, noticing a “particular change in behavior” over the last month as he smoked marijuana, Assistant District Attorney David Cutshall said during a Friday arraignment.

Matthew Paluzzi often argued with his mother and father at their home in the seaside neighborhood of Manomet, his half-brother told police during an interview Thursday. The last time the brother said he saw Paluzzi was at a family party last month, on July 3.

“During a conversation, the defendant said ‘I can’t wait for Anthony to die,’ referring to their father,” Cutshall said inside Plymouth District Court, where Paluzzi pleaded not guilty to one count of murder.

A Plymouth judge approved the defense’s ex parte motion for expenses for a forensic psychologist and continued the case to Oct. 2, coinciding with a probation violation hearing.

Authorities formally charged Paluzzi with the murder of his father Thursday afternoon, hours after police captured him in Hanover following a chase that spanned several South Shore towns.

Plymouth Police and EMS responded to 15 Cedar Road minutes around 6:30 a.m. Thursday, after receiving a call from the victim’s wife, Wendy Paluzzi, reporting she found her husband “unresponsive and bleeding from a laceration to the neck area.”

Police also found a knife resting on a towel near the front door of the Paluzzi’s raised ranch, Cutshall said.

“Wendy told police that her son … also lives in the house,” the prosecutor said. “However, he was no longer there at that time, and she did not know his whereabouts. She also discovered her vehicle, a black Nissan Murano, was missing from the residence along with her keys.”

“She stated she woke up early that morning when she heard the defendant inside the home,” Cutshall continued, “and she saw him walking from his bedroom toward the living room. When she got up and went to the living room she found the victim unresponsive.”

That prompted Plymouth Police to issue a bulletin with Paluzzi’s information and a description of his mother’s vehicle that he had taken.

A driver soon called 911 to report that she spotted the car in the area of Route 3A in Kingston. Authorities eventually stopped Paluzzi in the area of Washington Street, or Route 139, in Hanover, where officers took the defendant, wearing a hooded sweatshirt and sweatpants smeared with fresh blood stains, into custody.

At Plymouth Police headquarters, officers swabbed Paluzzi’s hands and tests came back with a “presumptive positive screening for the presence of blood,” Cutshall said.

“He initially told police that he would ‘tell you guys everything,’” Cutshall said. “He stated he had ongoing mental health issues and that he ‘snapped.’”

Police charged Paluzzi in October 2020 with assault with a dangerous weapon and threatening to commit a crime after he pointed a gun at a woman at a Plymouth ATM drive-thru, asking her “Do you want to die?”

Paluzzi had been licensed to carry a firearm, but the license was revoked following the incident, said Cutshall who described the case as a “seemingly random act of violence.”

The defendant admitted sufficient facts to that case in November 2022, leading him to be placed on a two-year probation that was set to end on Halloween, per court records.

The case caused Paluzzi’s mental health to “spiral,” his mother told police. An argument Paluzzi had gotten into last summer with her and her husband prompted their son to be hospitalized at a High Point Treatment Center and McLean Hospital, a psychiatric center in Belmont, Cutshall said.

As police canvassed the Manomet neighborhood Thursday, a resident highlighted an event from last August where she heard Paluzzi yelling at his father outside their home, the prosecutor said.

“She recalled the defendant saying ‘I’m going to (expletive) kill you,” he added.

Speaking with reporters outside of court Friday, Plymouth District Attorney Tim Cruz called the incident a “terrible situation” and said he feels bad for the Paluzzi family and Plymouth, as a whole.

“I am hopeful that in this situation as we go forward,” Cruz said, “people may learn something from this: How can we prevent the challenges we face in this world of mental health issues and drug issues, which are completely unabated in some instances?”

“We see it all around us right now,” the DA added, “and we as a society need to stand up and do better than that. But I also think that regarding criminal cases, the fact that somebody may have mental health issues doesn’t mean they’re not competent, doesn’t mean they’re not criminally responsible.”

Plymouth County District Attorney Tim Cruz speaks to the media after Matthew Paluzzi was arraigned on a murder charge in connection his father’s death. (Stuart Cahill/Boston Herald)