A Metro employee was shot and killed and three others were left injured in a shooting on Wednesday morning at the Potomac Avenue Metro station in Southeast D.C.

The alleged shooter was taken into custody, and on Wednesday night the Metropolitan Police Department identified him as Isaiah Trotman, 31, of Southeast. He has been charged with first-degree murder while armed, kidnapping while armed, and assault with a dangerous weapon. Police say they continue searching for a possible motive.

According to D.C. and Metro officials, the incident began when Trotman allegedly displayed a gun while on a bus approaching the station. He’s said to have exited the bus and followed a customer before shooting that person in the leg.

Trotman then allegedly entered the station and confronted a second customer who was trying to purchase a farecard before also shooting the person in the leg. He then moved to the station platform and confronted another woman, at which point witnesses report that a Metro employee tried to intervene and was shot.

On Wednesday afternoon Metro identified the employee as Robert Cunningham, 64, a mechanic in the power department. The transit agency lowered its flags to half-staff in his memory. “His heroism has to be recognized here today,” said MPD Executive Assistant Chief of Police Ashan M. Benedict. “Our thoughts and prayers go out to him and his family and the heroic actions he took took place here today.”

Witnesses have reported that a second Metro employee subsequently intervened, which helped bystanders tackle Trotman to the ground and stop him. Benedict said he wished officers, who responded in minutes, could’ve been there sooner. “The fact that our citizens have to intervene with an armed gunman is disturbing to me,” he said.

At a press conference, Metro General Manager Randy Clarke called it a difficult day for the transit system.

“It’s a brutal day. People are hurting,” he said of employees. “The people who work at Metro are public servants and they come to work everyday serve the community. To think someone showed up today to do their job and intervened to protect another person that lives here and lost their life is really sad. I hope we can reflect on that and give thanks to people who work so hard for us in public service everyday.”

Just last Thursday, Clarke honored two other Metro employees for acting valiantly during shootings – one at Metro Center and another on the 54 bus in Brightwood. Asked how he feels about Metro workers becoming de-facto first responders that are running into dangerous situations more often, Clarke said his number one worry every day is the safety of his workers and passengers.

“The people (that work) here are good people that are trying every day to do the right thing by their community,” Clarke said at a press conference last week . “The community they serve are their neighbors, their friends and family, the people they go to church with.”

Police say Trotman’s possible motive remains unclear, but the shooter was “clearly agitated.” The Washington Post reported that Trotman said “I’m the killmonger” as he proceeded into the station.

According to court databases, Trotman had no legal run-ins in D.C. or Maryland. In Virginia, a court database includes a small number of traffic citations and a late-2021 arrest for assault in Charlottesville, though that charge was dismissed last year.

Trotman was arrested on several drug charges and public intoxication last April in Adams County, Pennsylvania. Police were called to a local motel where workers said he was acting erratically and confronting guests, according to the District Attorney’s office. Trotman had water bottles in each hand and said his legs would not work if he let go of them, according to arrest documents. Police found 12 bags of meth, marijuana, and other paraphernalia in his SUV. Three weeks ago, Trotman pled guilty to one drug charge in the incident, which carries a sentence of up to 15 years. He was due to be sentenced on April 17.

There is no indication yet where and how Trotman obtained his gun, but it was one point that local officials focused on in their comments after the shooting.

“America has a disease of gun violence,” said Clarke. “Most of these situations, were just the random place where sometimes someone crosses paths with someone else, but there’s no actual targeted kind of gun violence on Metro itself. If anything, we’re the fabric of the community. We’re the vessels of and the veins of the community, and therefore naturally, you’re going to have people interact with each other.”

In her own comments, Mayor Muriel Bowser echoed concerns about the increasing number of guns that have come into the city and are being used in more crimes. While overall rates of violent crime have remained steady in the city, the number of gun-related incidents has increased in recent years.

“We’re focused on how we get guns out of our city,” said Bowser. “We know we have guns that are creating tragedies in our city and our nation.”

According to D.C. officials, police recovered 3,152 guns in 2022, an increase over the 2,310 recovered the year prior. They have also seen a spike in the number of “ghost guns,” or those made from kits and without serial numbers.

In their own statement, the leader of the Amalgamated Transit Union, which represents Metro workers, blasted the transit agency for what they said were failures to keep transit workers safe.

“I want to express our deepest sympathy and heartfelt condolences to the family and the loved ones of our fallen hero brother, who was tragically shot to death trying to stop the shooter. Our thoughts and prayers are also with our Local 689 members as they deal with this tragedy,” said President John Costa. “The scourge of violence on the D.C. Metro has gotten out of control and must be stopped. We hold the authority directly responsible for failing to protect our members and riders.”

The union cited other recent violent incidents in the Metro system, like a fatal shooting outside the Southern Avenue Metro station last month, and a pair of shootings in December at the Benning Road station and at Metro Center. None of those incidents injured Metro workers, though, and a union list of violent incidents on transit systems across the country going back as far as 2018 shows no prior violent incidents that killed Metro workers.

“Our union demands that federal and D.C. Metro government officials bring the same sense of regret that they will display in the public mourning of this tragic, unnecessary death of our brother and actually do something that will help to prevent these tragedies from happening. Transit workers cannot do their job, and passengers cannot travel on public transportation in fear of being attacked and assaulted,” Costa added.

Clarke says Metro has increased transit police presence, added four mental health crisis counselors, and adding more cameras to the system. “Metro is doing everything it can. Everyone is obviously frustrated with this problem, but this is not a D.C. or DMV issue either. It’s an American issue.”

This post was updated with a statement from the union that represents Metro workers, and with the name of the alleged shooter and information on past arrests.