CHICAGO (WLS) — A person armed with a knife took a gun from a CTA train passenger early Tuesday morning before shooting two men, killing one, Chicago police said.

The shooting is at least the fourth violent incident on a CTA train or bus since Friday, which is when the agency added police and private security to the system in hopes of reducing such crime.

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Police said the shooting happened on a CTA Pink Line train at about 1:22 a.m. in the 100-block of North Wells Street.

Two victims, 23 and 44 years old, were arguing with a male suspect, who was armed with a knife, police said.

Police said after the argument became physical, one of the victims took out a gun. The suspect was able to get control of the gun and fired, hitting the two men.

The 44-year-old man, shot in the abdomen, was transported to Northwestern Hospital, where he was pronounced dead, police said. The Cook County Medical Examiner’s Office identified him as Raymond S. Harrison Jr.

The 23-year-old man, shot in the wrist, was taken to the same hospital, where he was listed in fair condition, police said.

The suspect fled the scene and is not in custody, police said. Area Three detectives are investigating.

“It definitely is troubling. I think security should be a top priority on the CTA, because people should feel safe when taking it,” said CTA passenger Jack Gauer.

READ MORE | 7 suspects wanted for robbing CTA Red Line train passenger at gunpoint, police say

The shooting investigation disrupted trains in the Loop, before service began resuming at around 5:30 a.m.

People riding the L downtown later Tuesday morning, just two days before Christmas, were mostly unaware of another violent incident on a CTA train that happened just hours earlier.

“We’re just doing some last-minute Christmas shopping,” said CTA passenger Ben Blade.

Mayor Brandon Johnson addressed safety on the CTA on Tuesday.

“What works has to be properly funded, right?” Johnson said. “Our approach has been pretty straightforward, that working with Springfield to get the necessary resources added to our public transportation system, so that we can continue to grow the full force of government.”

Johnson continued, “Policing, preventative service, mental health support services, all of that is necessary… And I’m confident that as these investments continue to take hold, we’re going to continue to see what we have seen thus far, is that violence continues to go down.”

There is increased scrutiny surrounding the safety of passengers on the CTA, not to mention pressure from the federal government to make changes or or lose up to $50 million in funding.

The shooting comes only days after CPD and the CTA released details of a new, so-called “Security Surge Plan.” But last week, the Federal Transit Administration rejected the plan hours after it was implemented.

The CTA’s plan included more police, private security, and K-9 security staffing. The plan also includes expanding a voluntary program that allows officers to sign up to patrol the CTA on their days off.

However, the Federal Transit Administration believes the plan does not go far enough and is urging the CTA to take more aggressive crime reduction measures to protect riders.

“Chicago kind of gets that lens put on it that we’re, like, really, really dangerous and scary, and it’s unfortunate that this stuff is happening, because it’s kind of just exacerbating that stereotype about Chicago,” said CTA rider Geneva Swager.

Tuesday’s deadly shooting suggests that there is work to be done, as do other recent incidents on CTA property.

“When it comes to a shooting on a train, yeah, it does make you think and makes you want to be a little bit more aware of your surroundings, for sure,” said CTA rider David Granados.

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Before Tuesday’s shooting, three suspects allegedly carried out a knifepoint robbery on a CTA Red Line train on Monday.

And a woman is facing charges for allegedly battering two people on a West Side CTA bus on Sunday.

A man is also charged with setting a fire on a CTA Blue Line train near Damen on Friday morning.

But while there have been several high-profile violent incidents on CTA trains in recent weeks, according to CPD data analyzed by the ABC7 Data Team, violent crime on CTA buses, trains, platforms and stations is down 2.3% year-to-date through mid-December.

“I think mine is very safe, the Brown Line. I take that every day, and I’ve never had an issue there,” said CTA passenger Danny Less.

However, shootings are up year-over-year, from eight shootings last year to 12 this year, not including Tuesday’s shooting on the CTA Pink Line.

READ MORE | Man accused in Blue Line fire attack pleads not guilty in indictment that includes City Hall blaze

“You always try to be aware when you travel in the big city,” CTA passenger Betsy Getz.

In light of recent violent events across the transit system, members of Violence Interrupters deployed 25 outreach workers on the CTA Red Line in an effort to keep commuters safe.

“You have everyday people here that board the trains, that go to work every day, and then, somebody hit them in the head, and now, they are in the

hospital,” Tio Hardiman of Violence Interrupters said. “They lost their money. They might not be able to go to work and pay their rent. We are tired of that kind of stuff.”