(CNN) — An agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives was shot during an operation Thursday, the agency said.

A $25,000 reward is being offered for any information leading to the arrest of 25-year-old Bernard Graham.

Officials announced the suspect information and reward in a news conference Friday morning.

Agents from the Chicago Field Division were “ambushed” while conducting an undercover operation in Gary, Indiana, ATF Agent Brendan Iber said in a news conference.

“One of our agents was shot multiple times and was transported to the Methodist Hospital here at Northlake campus,” Iber said.

The wounded agent was in critical but stable condition, Iber added.

During the news conference Friday, investigators revealed the agent had been shot in the chest and upper left arm.

Investigators say Leandre Smith, 29, was attempting to illegally sell handguns to an ATF informant in a parking lot in Lansing, Illinois.

The agents, along with an informant, traveled to Gary, Indiana, where Smith introduced them to 28-year-old Raymond Truitt, II. Also present were Bernard Graham and Blake King, 19.

Truitt told the informant to check out the gun that Graham was carrying.

King then handed a bag to the informant that he claimed contained guns.

When the informant put bag on the ground to look inside, he realized it had kitchen pots and pans inside.

That’s when King, pulled the informant’s shirt over the informant’s head and Truitt and Graham fired on the ATF undercover agents.

Truitt was killed was killed in the shootout.

King is in federal custody.

Smith is in custody but has not charged.

Graham remains a fugitive.

The Chicago Police Department expressed solidarity with the agency after the news broke.

“Thoughts and prayers for the @ATFHQ Chicago Field Office agent who was shot and critically wounded in Gary, Indiana,” the department said in a tweet.

“ATF agents are working with us every hour of every day to reduce gun violence in Chicago and it’s beyond a partnership, it’s one team, one fight.”

The FBI’s gang response investigative team responded to the scene to assist ATF, FBI Indianapolis Public Affairs Specialist Chris Bavender said. The Indiana State Police are also investigating.

Elsewhere in Gary, more people were injured in a car crash after the shooting. Amid reports that the crash was related to the shooting, ISP released a statement detailing the wreck.

“This afternoon at approximately 12 p.m., the Lake County Sheriff’s Department was involved in a pursuit in Gary that resulted in multiple people being injured. Preliminary investigation indicates that a white Kia Optima fled the scene of a traffic stop at 7th and Tennessee in Gary. As officers pursued the vehicle, it fled southbound on Broadway. As it entered the intersection of 21st Ave at a high rate of speed, it struck two other vehicles,” the statement said.

“The identities of the drivers and passengers and all who were transported for treatment is still under investigation. There were earlier reports that this crash was related to an officer involved shooting. That shooting is being investigated by the Indiana State Police,” the statement continued. “The reason the driver fled which then resulted in the subsequent pursuit and crash is still under investigation.”

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