Domingus Nobrega stands with his attorney Tina Nadeau during his arraignment at Cumberland County Superior Court in Portland for his arraignment on Friday. He faces one count of murder in the death of his roommate, Matthew Merrick, of Portland. Gregory Rec/Portland Press Herald

A Portland man accused of killing his roommate late last year allegedly stabbed him to death in front of another person, according to court documents released Friday.

Domingus Nobrega, 48, has been charged with killing 43-year-old Matthew Merrick, whose body was found in a West End apartment on Nov. 30. Nobrega has been held without bail in Cumberland County Jail on one count of intentional or knowing murder since his arrest.

During his appearance Friday in Cumberland County Superior Court, Nobrega told Justice Deborah Cashman that he did not understand the charge against him. Cashman then read the charge to Nobrega, who still declined to enter a plea. She said the court would enter a not guilty plea on his behalf, so his case may proceed.

Police have said little about the suspected murder, including how Merrick died. But newly unsealed court documents detail accounts from multiple witnesses, including one who told police she saw the killing inside the apartment at 24 Marshall St. The Office of Chief Medical Examiner determined Merrick’s death to be a homicide and the cause to be a stab wound to the chest.

The documents do not, however, point to a particular motive or identify a specific weapon used to kill Merrick, whom friends and family have described as a hardworking, passionate man who used to work as a cook in Portland.

Nobrega’s attorney, Tina Nadeau, said her client is innocent. She said she doesn’t even know what the state’s case is, because she hasn’t seen any discovery outside of the probable cause affidavit, which only summarizes the accusations against Nobrega.

“The state of Maine and Portland Police Department have not provided a single bit of evidence to corroborate any of the allegations that are laid out in the affidavit,” Nadeau said in a phone interview Friday.

DAY OF THE KILLING

Nobrega told police he was doing laundry at Soap Bubble on Pine Street before he arrived home and brought Merrick his mail, according to court documents. The suspect has said, both in handwritten motions and in phone calls to a reporter, that he called 911 after finding Merrick unresponsive on the floor of his bedroom.

One woman told police that she was asleep in Merrick’s room that afternoon when Nobrega opened the door and stabbed Merrick at least once. She said she saw an Army-style knife in Nobrega’s room. She said Nobrega then gave her drugs and told her to call 911 and blame the stabbing on someone else, according to the affidavit.

The woman told police she left the apartment about 4 p.m., near the time Nobrega went to the laundromat. He was captured on the laundromat’s security footage pacing back and forth and using his phone from about 4:20 p.m. to 5:20 p.m., the affidavit states. He left and called police at 5:27 p.m.

Detectives wrote that several drugs were present in the apartment when police arrived. They found Merrick laying face down on the floor with cuts on his face, chest and collarbone area. They noticed a hammer and knife on the floor.

The responding officers patted down Nobrega, who told them he was carrying two knives and a multi-tool.

Another roommate, whom police found with headphones on in his room, told officers Nobrega told him that Merrick had died, according to court documents. He said he’d heard a man and a woman yelling earlier that day but assumed they were just being noisy.

Two Portland detectives said they tried to interview Nobrega, who declined to answer questions without an attorney, and then “collected his clothing” from him. They found a small apparent bloodstain on the right cuff of his shirt and a handkerchief that also appeared to be stained with blood, court documents read.

Nobrega maintains that he was improperly arrested and searched by police.

Nadeau, Nobrega’s attorney, filed a motion last month asking for prosecutors to turn over evidence in her client’s case, saying she had not received a “shred” of evidence in the more than two months since his arrest, which occurred three days after Merrick died.

A spokesperson for the attorney general’s office said the motion was premature because prosecutors generally provide discovery within 90 days.

Nobrega’s criminal history in Maine includes multiple felony charges since 2020 that were all dismissed, including an arrest for domestic violence aggravated assault.

He and other residents at the York County Jail also filed a lawsuit against the sheriff over COVID-19 protocols in 2020, which was ultimately dismissed in October 2024. He received a settlement of $6,900, according to documents provided by the Maine County Commissioners Association.