• Authorities did a routine check on a parked train
  • They detained a man onboard then another man began shooting
  • The suspect barricaded himself in the bathroom afterward
  • He was later found dead in the bathroom

A shooting incident on an Amtrak train at a station in Tucson, Arizona, has left a federal agent dead and two enforcement officers injured.

The incident took place on a parked train from Los Angeles around 7:40 a.m. Monday. Members of the regional narcotics "alliance" of local and federal authorities were reportedly taking a man in custody during a routine check, Tucson Police Chief Chris Magnus said as per NBC News. At some point, another man on the train's upper deck pulled out a handgun and opened fire at the authorities.

"The suspect, after exchanging rounds with the officers, barricaded himself in the bathroom, which is on the lower level. ... Ultimately it was determined that the suspect in the bathroom was, in fact, deceased," Magnus told the outlet.

The train's 137 passengers and 11 crew members were able to safely evacuate into the station. None of them sustained any kind of injury, according to the outlet.

The other man who was detained on the train remains in custody.

One agent working with the Drug Enforcement Agency (DEA) was killed in the encounter while the other agent remains in critical condition. A Tucson officer who rushed to help after hearing gunshots was also injured but is now in a stable condition, Magnus said further.

"Tragically, this morning, two DEA special agents and a DEA task force officer from the Tucson Police Department were shot during a law enforcement operation in Tucson, Arizona," Anne Milgram, administrator for the DEA, said in a statement Monday.

"We at the DEA are heartbroken by today's events and ask that you keep the families of the agents and task force officer in your thoughts and prayers," Milgram added.

U.S. Attorney General Merrick B. Garland also released a statement Monday in connection with the incident.

"This past week has been a reminder for all of us at the Department of Justice of the risks our deputies, agents and local law enforcement partners confront each day," Garland noted. "We are grateful for the courage and selfless sacrifice of these heroes, and I join the entire Justice Department in conveying our support and deepest sympathies to their families."

An Amtrak train | Representational Image Getty Images/Mario Tama