Federal agent dead after attacking supervisor

A federal immigration agent was killed after shooting and wounding his supervisor in their office during a dispute, officials say.

The agent, a Homeland Security investigations officer, opened fire on his boss after being advised that disciplinary action was being taken against him, CBS News' John Miller reports. A third agent intervened, fatally shooting the attacker.

The wounded agent was taken to the hospital, where he is listed in stable condition and is expected to survive.

The names of the dead gunman, the victim and the agent who fired the final rounds were not released. The third agent was not harmed in the incident.

The cause and nature of the disciplinary action are unclear.

There were conflicting early reports about the number of people shot, with local authorities saying two were dead and one wounded, while Immigrations and Custom Enforcement said one was dead and one wounded.

The shooting happened on the seventh floor of the Glenn M. Anderson Federal Building in downtown Long Beach that houses ICE, the Internal Revenue Service and the U.S. Probation and Parole Office.

St. Mary's Medical Center Trauma Director James Murray told KCAL-TV that the injured agent sustained wounds to multiple parts of his body, but did not further specify. He said the victim's vital signs were "good for now," and that he had ongoing bleeding but that it wasn't a cause for concern.

"At times like this words honestly seem inadequate. When something like this happens in our offices, it's incomprehensible," ICE Special Agent in Charge Claude Arnold said.

Along with the FBI, the shooting was being investigated by ICE's Office of Professional Responsibility and Long Beach police.

Above, watch a report from Long Beach, Calif.