A Portland man has been charged with murder in the killing of an employee at a nonprofit residential facility, police say.

Armando Javier Negrete, 40, a resident of the Shalom House group home at 503 Woodford St., was arrested Monday, Portland police announced Tuesday morning.

Negrete is being held at the Cumberland County Jail without bail, according to jail staff.

He is accused of fatally stabbing Marlene McNeill, 40, of Gorham. McNeill was taken to Maine Medical Center, where she was later pronounced dead, police said.

Shalom House, a Portland nonprofit that runs housing programs for adults with severe mental illness, confirmed Monday evening that an employee died in “a tragic incident this morning involving violence.”

“Our deepest condolences and thoughts are with our employee’s family and her large community of friends, which includes her Shalom House community,” the organization said in a statement it released through its attorney. “Our immediate focus is the well being of her family, our employees and our clients.”

Mea Tavares, who worked with McNeill at Shalom House just over a decade ago, described her as a caring, hardworking person who knew how to deescalate conflict.

Tavares, 42, of Stockton Springs, was shocked to learn about the stabbing, which happened at the same group home where the two worked together.

While the job can be stressful, Tavares said McNeill was a grounded and compassionate worker who wanted to help others thrive. The eight-hour shifts at the group home included administering medication to residents and helping them with daily needs, Tavares said.

Tavares said McNeill’s death is a tragedy that highlights the importance of mental health resources.

“People like Marlene who are just showing up every single day to do their own individual part to help people live resourced, joyous, thriving lives … it’s all part of a bigger picture of a world under a lot of stress,” Tavares said.

Police were on the scene at the home near the intersection of Woodford Street and Rosemont Avenue, just off Brighton Avenue, for several hours Monday. As they took photos and interviewed residents, onlookers told a reporter that police activity is unusual in their typically quiet neighborhood.

Other residents of the home were evacuated from a second-floor window to avoid the crime scene inside the building’s hallway, according to police officials. First responders directed the residents out of the window onto the extended ladder of a fire truck.

A knife could be seen lying in an adjacent yard, which police had marked and blocked off with crime scene tape.

Negrete is scheduled to make his first court appearance Wednesday afternoon, according to the Office of the Maine Attorney General.