The Glock 17 rested in a display case in a gun shop in a Virginia strip mall.

Black. Easy to shoot, easy to handle. A used 9mm. For $325 in cash, it was sold to a man who swore in writing on a federal form that the gun was for him.

It wasn’t.

Within days he’d pass the semiautomatic to a friend who had driven him to the store. That friend passed it to others.

Six days after the Glock was purchased on Aug. 4, 2014, it was used in a gun battle that wounded six at a birthday barbecue a few blocks from Nationals Park.

It was fired three days later at a woman driving along a District highway listening to R&B, a victim who happened to be an off-duty D.C. police officer headed home from a nightclub. She kicked off her Louboutin heels and punched the gas pedal trying to catch the shooters.

The same night and less than two miles away, the Glock was fired again at a man stopped at a traffic light in a hulking Yukon Denali. In a coincidence, he, too, was a cop and a random target, in plain clothes and driving into the District to testify in a murder trial.

Shot four times, desperately trying to get to his service weapon in a gym bag on his front seat, the officer rammed his SUV into the shooter’s car to try to force it to stop.

The officer never managed to fire a round, and the gunman with the Glock got away.

The Yukon Denali driven by Detective Thurman Stallings was hit a dozen times by a shooter using a Glock 17 pistol in the District in August 2014. Stallings was hit four times. (U.S. Attorney’s Office for D.C. )

The Glock 17 was brought to the nation’s capital in 2014, one of 2,178 illegal guns taken off the streets that year by police in the District. Since then, nearly 5,000 more guns have been seized in raids and found during arrests and at crime scenes.

The path of the Glock was tracked through court files, interviews, photos, surveillance videos and a 911 call. To follow the saga is to understand the devastation and suffering that just one gun can cause.

It changed hands at a rapid pace and traveled across state lines — stashed in houses, a glove compartment and a flower pot before being tossed under a car in a panicked sprint from police.

The Glock was shared in just three months by the two men who started its trafficking at the strip mall and at least five more people who knew how to get to the gun when they needed it and how to pass it off when they didn’t.

The speed at which guns move from sale to use in a crime is breathtaking, and the Glock’s story demonstrates why law enforcement officials say they often are playing catch-up to the firearms in urban areas. And as the Trump administration and others draw attention to violence in cities, big city mayors and police chiefs point to the easy availability of illegal guns as a driving factor.

Guns in high-crime areas “are not disposable commodities” and tend to stay within a group even after they’ve been used in crimes, said Daniel L. Board Jr., who runs the Baltimore Field Division of the Bureau of Alcohol, Tobacco, Firearms and Explosives.

In recent years, investigators in the District have uncovered what they dub community guns hidden under a refrigerator at a drug stash house and beneath the front stoop of a home.

But the ever-more-rapid pace from purchase to street use is ominous even to experts who have tracked firearms for years.

The span between when a gun is sold and its use in a crime in the District has shortened every year since 2010, ATF tracking shows, and the number of guns showing up in crimes within three months of their sale has doubled over the past five years.

“The bottom line,” Board said, “is that when we see those short time to crime spans, our immediate thought” is the link to violent crime.

How the number of guns recovered in D.C. compares with other cities

Guns recovered per 100,000 people from 2010 to 2016

Orlando

3,960 guns

Baltimore

2,578

1,540

Washington, D.C.

908

Los Angeles

New

York

322

Source: Bureau of Alcohol, Tobacco, Firearms and Explosives

How the number of guns recovered in D.C. compares with other cities

Guns recovered per 100,000 people from 2010 to 2016

3,960 guns

Orlando

2,578

Baltimore

1,540

Washington, D.C.

Los Angeles

908

New York

322

Source: Bureau of Alcohol, Tobacco, Firearms and Explosives

The Glock 17 was part of a summer 2014 buying spree.

In the span of a month, Jamal Fletcher Baker and his buddy Lawrence Monte Morgan visited five Virginia gun dealers, spending more than $3,500 on a dozen firearms, court files show.

Sometimes they bought two at a time. Sometimes they doubled back to a store within days.

A Smith & Wesson pistol in Richmond. A Walther Uzi and a Ruger P345 in Ashland.

And at the Manassas store, the Glock.

Baker and Morgan weren’t experienced street hustlers when they teamed up in the gun scheme that authorities said included posting weapons for sale on Instagram.

Morgan grew up in violent neighborhoods in Maryland and the District. He had no job, was a new father and at the age of 24 was a rapper known as “Stunna.”

Baker was raised in a strict military family in Prince George’s County. He was 23 and selling shoes on the street.

The two had met a few years earlier while trying to break into the music industry.

Together, a court case would show, they went to Virginia Arms Co., about 50 miles from the District, on a late afternoon in early August and from a display, chose the Austrian-made 9mm Glock 17.

Baker filled out the required paperwork, Federal Form 4473, and declared he was buying the gun for himself — a lie that is a felony. He quickly gave the Glock to Morgan, the intended owner.

The path of the gun