For years, Tu Nguyen’s family feared him.
The 28-year-old Dorchester man had a long history of mental illness and violence. In recent years, he had punched a stranger at an arraignment, skipped out on court-mandated anger management classes and psychiatric evaluations, and kicked his younger sister so hard she was rushed to the emergency room, court records state.
On Jan. 26, the family filed a restraining order against him.
“My family is very concerned about our safe[ty] due to his threats [that he will] hit or punch or harm us in some way,’’ a family member wrote in an affidavit seeking the order.
Yesterday, Nguyen pleaded not guilty in Dorchester Municipal Court to charges of stabbing and killing his 72-year-old neighbor earlier in the day.
He was ordered to undergo a 20-day psychiatric evaluation at Bridgewater State Hospital and to return to court March 9 to determine if he should be released on bail.
The victim, Mary Miller, was a long-time Dorchester resident who was active in her church. More than 40 of her family members, friends, and fellow churchgoers poured into the courtroom to watch the arraignment, filling almost every bench.
At around 1:43 a.m. yesterday, police received a 911 call for a breaking and entering in progress at 45 Codman Hill Ave., an apartment adjoining the one where the Nguyen family lived.
When police arrived, a window at Miller’s unit was broken, and they had to break down the back door to enter. They found Miller with several stab wounds. She was pronounced dead at the scene.
A girl found inside the apartment was physically unharmed, but the child was taken to Boston Medical Center for evaluation, police said. The girl, whom authorities did not identify, is less than 10 years old, police said. Officials at the church where the victim attended said the girl is Miller’s granddaughter.
According to a police report, officials obtained video evidence that they say showed Nguyen entering and exiting Miller’s residence before and after the homicide.
Police arrested Nguyen at his house yesterday, hours after the killing. A motive for the attack was not immediately clear.
Shannon McAuliffe, the attorney representing Nguyen, said her client was given a preliminary psychiatric evaluation, in which he did not cooperate with the psychiatrist.
“It is unclear whether he understood the charges, the legal process, or who I am,’’ McAuliffe said.
Though Nguyen was brought to the courthouse, McAuliffe asked that he not appear in the courtroom. The child who witnessed the slaying had not yet identified a suspect in person, and media photographs of him at the proceedings might taint her recollections, McAuliffe said.
Most family members declined to talk with reporters after the arraignment, but a woman who identified herself as a sister of the victim said Miller was, first and foremost, a “church woman.’’
“We’re just shocked,’’ the sister said.
Joseph Rocha, a minister at Dorchester’s Grace Church Of All Nations, said Miller was a long-time member who volunteered at the church, offered prayers for others, and almost always came to service dressed all in white.
“Certainly you can see by the numbers here,’’ Rocha said, gesturing at the dozens in the courthouse lobby, “how well she was loved by many, not just in her family, but in the community.’’
The church’s senior pastor, Bishop A. Livingston Foxworth, recalled that Miller was talkative, never passing up an opportunity to get up and address the whole congregation.
“When something like this happens to someone so good, it’s almost impossible to say words that are encouraging,’’ Livingston said. “All we can say is, know that her life is not in vain, that somehow, something good is going to come out of this.’’Martine Powers can be reached at email@example.com. Follow her on Twitter @martinepowers.