Two armed robberies that occurred Sunday in Washington have been linked to an earlier spate of hold-ups in which Tasers were used to subdue or threaten victims, according to D.C. police.

The latest attacks were in Capitol Hill in Northeast Washington, in which a car was taken, and near the U Street corridor in Northwest. The robberies last week happened near the Washington Convention Center in Mount Vernon Square.

The latest robbery occurred about 8:40 p.m. Sunday in the 2100 block of 10th Street NW. D.C. police said that a man walking through an alley was hit with a Taser from behind and knocked to the ground. Police said items were taken.

Also on Sunday, police said a newspaper delivery man was robbed about 5 a.m. in the 1300 block of Tennessee Avenue NE in Capitol Hill. Police said a man threatened him with a Taser and said, “Give it up.” The victim gave the man his car keys, and the person drove off in a silver Toyota.

Authorities did not identify the company for whom the victim worked.

The other robberies occurred Sept. 23 and Sept. 24 near the convention center. In one case, police said one person was armed with a Taser and another with a handgun. In most cases, wallets and cellphones were stolen. One man was shocked with a Taser and repeatedly punched, and required hospital treatment.