PRINCE GEORGE'S COUNTY, Md. -- Police were going about their business on Sunday afternoon when a gunman fired at the first officer he saw outside a Maryland police station, prompting a gun battle that left an undercover narcotics officer dead and the suspect wounded, authorities say.

Prince George's County Police Chief Hank Stawinski said Jacai Colson, a four-year veteran of the department only days shy of his 29th birthday, died in the "unprovoked attack" outside the station. They posted a photo of Colson to Twitter.

Suspect ambushes officer outside Police Station; Officer fatally wounded. https://t.co/4LlkHTxBV2 pic.twitter.com/CyqMlszoXF — PGPDNEWS (@PGPDNews) March 14, 2016

The shooting erupted in Landover, a suburb about 10 miles northeast of downtown Washington, D.C.

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Speaking at a news conference, Stawinski said that once the first shot was fired, several officers fired back at the suspect. He couldn't say how many shots were exchanged in the confrontation that began about 4:30 p.m.

The police department said on Twitter that Colson "lost his life in defense of this community today. This was an unprovoked attack."

"Jacai had an infectious smile, he lit up a room," according to FOP President Zeek Teletchea, who called him a "cops cop" and personal friend.

Our officers were going about their business and were attacked. Fallen officer was 4 yr veteran. pic.twitter.com/HY8cU3nA8M — PGPDNEWS (@PGPDNews) March 14, 2016

CBS affiliate WUSA reports two suspects are in custody in connection with the shooting.

"Those officers did not shrink. They bravely advanced and engaged this individual who was threatening not just the police officers and the police facility that he was opening fire upon but numerous members of the community in the area," said Chief Hank Stawinski.

Police had initially posted a message on Twitter asking residents to avoid the area and to stay inside because of a possible "active shooter" situation. Police later said they don't believe there are any other suspects.

We have a 2nd suspect in custody. Prelim: we do not believe there are outstanding suspects but investigation is in early stages. — PGPDNEWS (@PGPDNews) March 13, 2016

Prince George's County State's Attorney Angela Alsobrooks called the shooting an "act of cowardice" and a "horrific act of evil." She promised an aggressive investigation and prosecution of the alleged shooter, who was wounded in the return fire but is expected to survive, and another suspect arrested soon after the shooting. Their names were not immediately released.

Stawinski said the second man was believed to have been present with the suspected shooter when the shots erupted, but fled and was later arrested. He gave no immediate indication what prompted the shooting.

The Washington Post reported that one woman near the site grabbed her sleeping, 14-month old baby from his play pen when she heard what she thought might be either firecrackers or gunshots. The woman told the newspaper she looked outside and saw a man dressed in black firing a handgun.

"He fired one shot, and then he started pacing back and forth, then fired another shot," said Lascelles Grant, a nurse. She added in the account that police began pouring out of the station. "Just looking outside, I'm like, 'Oh my God, look at all these police officers running out, putting their lives really in danger,'

The FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives were assisting local police in the investigation, spokesmen for the two federal agencies said. They said the Prince George's County Police remained the lead investigating agency.

Dave Fitz, spokesman for the FBI in Maryland, said the FBI "reached out and offered support" and sent a couple of special agents to assist. He had no further details.

Dave Cheplak, spokesman for the ATF in Maryland, was unable to say how many ATF agents were assisting. He also could not say specifically what they are doing, but said assistance typically would include following up on leads, interviewing witnesses, supporting evidence collection and tracing any recovered firearms.

Governor Larry Hogan issued a statement in regards to the shooting.

"I am shocked and saddened by the news this evening of the death of Prince George's County police officer Jacai Colson in the line of duty," the statement read. "Our administration is committed to assisting Prince George's County officials during this time, and the Maryland State Police are working closely with local law enforcement to provide support as needed."

Governor Hogan has ordered flags to fly at half-staff.