The robbery spree started in the middle of the afternoon, a man pointing a shotgun at a 13-year-old boy outside a Southeast Washington elementary school and demanding the child’s jacket. The boy struggled, police said, so the man hit him over the head with the butt of a shotgun before speeding off in a stolen green Nissan Altima.

Over the next 75 minutes on Wednesday, according to police, the gunman continued to search for victims, holding up three other people in two separate robberies.

A 19-year-old man from Southeast was arrested in Prince George’s County on Wednesday night after police said he got into a car crash in the District and fled into Maryland. He was being held there on a charge of unauthorized use of a motor vehicle.

D.C. police said they were seeking an arrest warrant to charge him in the robberies.

“The good thing was we had witnesses who were observant and provided tag numbers, said D.C. Police Cmdr. Robert Contee, who heads the 6th District station.

As he learned of the spree, Contee said, “I was confident that we would eventually get him.”

The robberies occurred a day after a teenager was robbed and shot in Southeast while headed to school. Police said the man arrested Wednesday is not linked to that attack, in which no arrest has been made.

Wednesday’s robberies came in rapid succession roughly along the Benning Road corridor from Marshall Heights in Southeast to the Minnesota Avenue Metro stop. Police said each involved a man with a shotgun jumping from a green Altima.

The first robbery targeted the 13-year-old, police said. It occurred about 3:45 p.m. at 50th and C streets SE, in the same block as Nalle Elementary School. A school system spokeswoman said the youth is in middle school.

Officer Araz Alali, a D.C. police spokesman, said the youth was attacked from behind by a man who pointed a shotgun at him and said, “Give me your jacket.” Alali said the gunman fled without taking anything after hitting the boy.

About 4:25 p.m., Alali said that two women in the 4000 block of Grant Street, near the Minnesota Avenue Metro, were robbed. Alali said the man got away with handbags, cellphones and credit cards.

About a half-hour later, a man in the 4400 block of A Street SE was robbed of his wallet and backpack, Alali said.

In a separate case, authorities with the Metro transit system said they arrested two juveniles in connection with an attack aboard a train at the Fort Totten station on Nov. 30, purportedly carried out by a group of young men calling themselves the “44th Street Crew.”

A video of the attack shown by local news stations shows young men and women accosting female students from the University of Maryland at College Park. The victims are seen fighting back as one man shouts “44” ; the fight spills onto the station platform.

Metro spokesman Dan Stessel said six youths were questioned and two were arrested in the case.