(STMW) — An off-duty Cook County sheriff’s officer shot and critically wounded a man who allegedy opened fire outside a bar in the River West neighborhood early Sunday.

The off-duty officer was standing across the street from the Funky Buddha Lounge in the 700 block of West Grand Avenue about 2:50 a.m. when he saw a man waving a handgun in a crowd, police said.

The man had been driving westbound on Grand Avenue when his vehicle struck several parked vehicles near the lounge, according to a police source. When patrons who were standing outside the club started approaching the man, he jumped out of his vehicle and fired shots.

The off-duty officer, who had been in a nearby establishment, saw everything, approached the man, announced his office and ordered him to drop the gun, police said. The man then turned toward the officer and fired more shots, police said.

The officer returned fire, striking the man multiple times, police said.

The 27-year-old man was taken to Northwestern Memorial Hospital, where he was in critical condition Monday morning, police said.

After he was shot, the man dropped his weapon, police said. While the officer was waiting for assistance and securing the man, a second male picked up the gun and also fired at least one shot at the officer.

The second shooter then got in the man’s vehicle and sped away, police said. The officer was not injured.

Police said the man who was shot is a documented gang member.

The investigation is ongoing by Area Central detectives.

Sean Currie, 33, who works at a nearby restaurant, was sitting in the Clover Sports and Leisure Bar next door when someone started banging on the bar’s side door.

As he opened the door and asked, “why are you banging?” he heard three gunshots. The people outside told him someone was shooting.

Two employees of the Funky Buddha, who declined to give their names, said they heard about seven gunshots, maybe more, right after last call as the patrons were filing out of the bar.

A police officer on the scene said that gang members hang out at the lounge, which he called a “problem child” for the neighborhood in the past.

A shooting was reported in the same block at 3:20 a.m. on Nov. 9, according to the City of Chicago Data Portal.

“Half of us (in the bar) were like, ‘here we go again,’” Currie said.

The Cook County Sheriff’s office confirmed a correctional officer was involved in the shooting, according to spokeswoman Sophia Ansari.

“While this incident is under investigation by the Chicago Police Department, it appears that our officer’s brave actions saved the lives of innocent people,” Ansari said.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2014. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)