FBI Special Agent Nolan Wells was killed in a shootout with federal agents in Nebraska, the bureau confirmed, in a rare and tragic attack on federal law enforcement.

Officials said Wells was shot during an exchange of gunfire while agents were carrying out an operation. He was rushed for treatment but did not survive. A suspect has been arrested in connection with the shooting.

The FBI said the incident is under investigation and declined to release further details about the operation or the suspect’s identity. Local and federal agencies are assisting with the probe.

The death of a special agent in the line of duty is a rare event that sends shockwaves through the bureau. Colleagues described Wells as a dedicated agent, and tributes poured in from across the law enforcement community.

The bureau said more information will be released as the investigation progresses. Officials have asked the public to keep Wells’s family and fellow agents in their thoughts during what the FBI called an extremely difficult time.