A man who was recently fired from his job at Navy Pier, a major Chicago tourist attraction, returned to his old workplace and killed two people before fleeing on Tuesday, according to police.

The attack occurred just before 1:20 p.m. in the administrative office at the loading dock on the north side of Navy Pier, Chicago Police Chief Patrolman Jon Hein said at a news conference.

The two workers who were shot, both men, were transported to Northwestern Hospital, where they were later pronounced dead, police said.

“This was an isolated incident by a disgruntled former employee,” Hein said.

Authorities said the attack did not occur in a public part of the tourist area, but Navy Pier was briefly locked down while the investigation continued.

Police are still actively searching for the suspect but have not publicly identified him, citing the department’s policy of not naming people unless they are charged.

The fatal attack occurred a day after Chicago police officer Enrique Martinez was shot and killed in the line of duty. The events are not connected.

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