A man in police custody opened fire on officers at an Endeavor Health Swedish Hospital campus in Chicago on Saturday, killing one officer and leaving another critically injured, according to Chicago police officials. Chicago police Superintendent Larry Snelling said the officers were transporting the individual for an observation at the hospital when two of their colleagues were shot. Snelling said one officer was pronounced dead, and the second was in critical condition as of Saturday evening.

Snelling described the sequence at a news conference, saying “Officers transported an individual over to the Swedish hospital for an observation, at which time two of our officers were shot.” He said, “One was shot critically. It (the death) was pronounced. The second officer right now is fighting for his life in the hospital behind us,” adding that the investigation was ongoing and he would not provide further details.

Officials said the suspect was not publicly identified. Police said the man fled the hospital after the shooting, which occurred around 10:50 a.m., and later was detained, with a gun recovered. The hospital said its campus was placed on lockdown and that patients and staff were safe during the incident.

The hospital also said the person in custody was brought to the emergency department for treatment and was “wanded upon arrival,” following its protocols. The hospital said the man was escorted by law enforcement at all times. In a Facebook posting, the hospital said the individual later fired shots at the law enforcement officers and exited the hospital building.

At the same news conference, Mayor Brandon Johnson said the day was especially difficult for the city. “Today is a real difficult moment for our city. It’s a tragedy,” Johnson said, and he said Chicago was providing mental health support services to police officers so they can continue their jobs.

Snelling said the officers had been assigned as transport officers, and he said a weapon was recovered. He added that the names of the officers were not released because they want to be sure that their families have been notified. Snelling said one officer was 38 years old and had worked for 10 years in the department, and the other was 57 with 21 years of service.

Police said the officer remained in critical condition Saturday evening, and they did not release further information about the suspect or the investigation while authorities worked to determine what led to the shooting. As officers and hospital staff coordinated their response, the incident underscored the risks that can arise during custody transfers and security situations inside medical facilities.