Police also confirmed today that the wounded officer had a body camera, but that it was turned off during the incident.
St. Louis County Police Sgt. Brian Schellman, a police spokesman, said he did not know why the camera was off.
Ferguson police officers began wearing body cameras on Aug. 31, three weeks after a white police officer, Darren Wilson, fatally shot Michael Brown Jr., an unarmed black teenager.
Police originally reported late Saturday night that the officer spotted two suspects trying to break into a business and that when confronted, one of them pulled a gun and fired at the officer, wounding him in the arm.
Police, however, now are describing a different scenario: that the police officer, during a business check, saw a male subject in the rear of the Ferguson Community Center. When he approached, the person began to run and the officer followed on foot. During the pursuit, the man spun around and fired at the officer, who was hit in the left arm, before disappearing in the wooded area behind the center.
The officer was treated and released from a local hospital today.
Ferguson Police Chief Thomas Jackson and St. Louis County Police Chief Jon Belmar were originally told that the incident involved two suspects at the time they provided statements to the press Saturday night, but later detectives confirmed it was only one individual, Schellman said.
Schellman also said that police did not have any more details on suspect's description.
The earlier story:
FERGUSON -- A Ferguson police officer was shot Saturday night. The officer, a man, survived the shooting, authorities said.
The shooting occurred in the 1000 block of Smith Avenue in Ferguson, near the new Ferguson Community Center.
Ferguson Police Chief Thomas Jackson said Saturday night that the officer was on routine patrol and spotted two suspects trying to break into a business. He said the business was in Ferguson.
When the officer confronted the suspects, Jackson said, one of them pulled a gun and fired at the officer. The officer was struck once in the arm, and was expected to be OK.
At a news conference near the Ferguson Police Department early Sunday, St. Louis County Police Chief Jon Belmar gave the same account of the shooting as Jackson.
He added that police fired at the suspects at some point during the altercation. But there is no evidence that they were hit. "We have no indication either suspect was shot," Belmar said.
Belmar said he doesn't believe the incident was linked to the Ferguson protests, and that he knew of no other incidents Saturday night.
In the background, chants could be heard from protesters, including, "We are going to shut this down!"
Many in the group of roughly 100 expressed skepticism at the police account of the shooting.
Dozens of police cars from numerous jurisdictions converged on the area after the shooting. The shooter is reported to have fled into nearby woods.
Police established a staging area near the St. Peters Evangelical Church of Christ on West Florissant Avenue.
Officers are still searching for the shooter, according to St. Louis County Police.
The shooting came at the end of another week of protests, arrests and violence since the Aug. 9 shooting of Michael Brown by Ferguson police Officer Darren Wilson.
Authorities had hoped to avoid further confrontations by canceling the weekly Ferguson Farmers Market on Saturday to prevent a repeat of last week's encounters between protesters and marketgoers.
Ferguson Police Chief Thomas Jackson issued a video Thursday in which he apologized directly to Brown's family and to protesters who felt the police mishandled the protests that followed. But the move seemed to reignite protesters calling for Jackson's firing, and tension increased.
Christine Byers, Nick Pistor, Steve Giegerich and Denise Hollinshed of the Post-Dispatch contributed to this report.
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