NORRISTOWN >> Weeping at times, a Conshohocken man admitted to fatally stabbing his aunt more than 30 times during a confrontation in her home where he was staying and learned he’s headed to prison for up to four decades.

Matthew Joseph Wertz Jr., 29, was sentenced in Montgomery County Court on Monday to 20 to 40 years in state prison after he pleaded guilty to a charge of third-degree murder in connection with the 5:14 a.m. Dec. 16, 2016, stabbing death of his 60-year-old aunt, Catherine Wanamaker inside her home in the 900 block of Hallowell Street.

The sentence was imposed by Judge Thomas C. Branca, who accepted a plea agreement in the case.

Third-degree murder is a killing committed with malice.

“The defendant is admitting that he stabbed his aunt, the victim in this case, to death. The tragedy is that she was trying to help him,” county Deputy District Attorney Samantha Cauffman said after the brief hearing.

“He had a tremendous drug addiction problem and she was, in his words, ‘controlling him’ by trying to keep him away from the very substance that was going to kill him in the end. And because of that he killed her,” Cauffman alleged.

Previously-filed court documents indicated Wertz, who is disabled after the amputation of his right arm and leg, had a substance abuse problem, including a heroin overdose and hospitalization on Dec. 12 and Dec. 13, 2016, just days before the fatal stabbing of his aunt.

Detectives alleged Wanamaker suffered more than 30 stab wounds to the back, chest, face, head and neck as well as “defensive” wounds to both hands.

A more serious charge of first-degree murder, which is an intentional killing, was dismissed as part of the plea agreement. A conviction of first-degree murder carries a sentence of life imprisonment.

“Given all of the other facts and circumstances of this particular case, a plea to 20 to 40 years for murder of the third-degree was appropriate and justice was served, given the unique set of circumstances of this case,” Cauffman said.

Wertz, who was represented by defense lawyer Carrie L. Allman, at one point during the proceedings, uttered, “I deserve the death penalty.”

Wertz also seemed to indicate at one point that he couldn’t remember the exact moment of the stabbing but said prosecutors had the evidence to prove he committed the crime.

“I want to apologize to my family,” Wertz, wearing a red prison jumpsuit, sobbed.

Wertz, who suffered the loss of his right arm and leg, was brought to court in a wheelchair. The judge recommended that Wertz be incarcerated at the Pennsylvania Department of Corrections’ facility at Laurel Highlands in Somerset County, a minimum-security institution for the infirm.

Several relatives of Wertz and Wanamaker were in court to witness Wertz’s admission.

Wertz had been living with Wanamaker since being released from the county jail on Dec. 12, 2016, detectives said.

Previously-filed court papers revealed Wertz was treated at Delaware County Memorial Hospital for a drug overdose on Dec. 12, just hours after being released from jail and days before Wanamaker’s murder.

An investigation began when police responded to the home after a 911 caller reported he heard a woman screaming for help and a dog barking for an extended period of time. The caller described Wanamaker’s voice as sounding “very distressed.”

When Conshohocken police arrived at the home they found it locked but when they peered inside a front window they observed a male looking at them and then quickly dart out of sight, according to the criminal complaint filed by county Detective Paul Bradbury and Conshohocken Detective William Walter.

When the officers forced their way inside the home they saw Wanamaker dead on the living room floor and Wertz several feet away kneeling with his back toward officers and he ignored officers’ commands.

“As the officers approached Wertz they observed a knife in his hand and he appeared to be stabbing himself in the throat area with the knife,” Walter and Bradbury wrote in the arrest affidavit.

When Wertz ignored verbal commands to drop the knife, police utilized a Taser device to disarm him, according to court papers.

After the Dec. 16 fatal stabbing Wertz, according to court documents, was transported to Lankenau Medical Center to be treated for self-inflicted wounds to his neck area and was released to the custody of authorities later that same day.

Detectives seized a blood-covered kitchen knife with an approximately six-inch blade in the dining room of the home during the investigation, court papers indicate.

During the investigation, Wertz’s mother told detectives that her son was living with her sister, Wanamaker, “because he was disabled and she had offered to take care of him,” according to the criminal complaint.

Wertz’s mother told detectives her son abused heroin, painkillers, crack cocaine and “pretty much whatever he could get his hands on,” and said her son gets angry and acts out when “he needs drugs or wants to get drugs,” according to the arrest affidavit.

Court records show that Wertz had previous convictions for retail theft, disorderly conduct, possession of drug paraphernalia and receipt of a controlled substance by unauthorized person dating back to 1996.

When detectives interviewed Wertz regarding his aunt’s death he allegedly stated, “I did it, I was not in my right frame of mind when I did it” and then refused to provide any further information about his aunt’s death.