BOSTON — A hospital that treated a man before he fatally stabbed two people and wounded several others at a home and mall said Thursday that it was barring a state contractor that provides mental health evaluations.

In a letter to state officials, Morton Hospital said the contractor, Norton Emergency Services, was putting patients at risk by not providing “critical and timely services.”

The hospital did not reference the case of Arthur DaRosa, the assailant in the stabbings. His family said he had been battling mental illness in recent months and was suicidal and depressed when he checked himself in to Morton Hospital on Monday evening. He was released Tuesday morning and hours later fatally stabbed an 80-year-old woman in her home and a 56-year-old teacher dining out at a mall with his wife before being shot and killed by an off-duty sheriff’s deputy.

The hospital took the action against Norton Emergency Services unilaterally after it failed to evaluate several patients in its emergency department in a timely way Thursday morning, and the hospital was “rebuffed or ignored” when it offered to perform the evaluations themselves, a spokeswoman said in a statement.

A message left with a spokeswoman for the contactor was not immediately returned.

Norton Emergency Services is run by the state Department of Mental Health and is one of four Emergency Services Program providers operated directly by the state.

The hospital said earlier that state policy governing the way it handles psychiatric patients was “misguided.” It said the state should review and revise policies that require outside third-party vendors to evaluate and recommend the treatment provided to Medicaid patients in emergency departments. The hospital said its own psychiatrists and clinicians should be allowed to assess patients.

Morton also said psychiatric beds were available Monday.

“If the state contracted agency responsible for conducting evaluations in the emergency department had requested an admission to a psychiatric bed, there were beds available within the hospital’s network,” said Julie Masci, a spokeswoman.

Republican Gov. Charlie Baker declined Thursday to address specifics of the case or current state policies, but promised the state would investigate procedures.