District police are investigating three violent robberies — two of which left victims tasered and others beaten — that occurred this week near the Washington Convention Center in Mount Vernon Square, according to authorities.

Police said one of the victims did not report being robbed until Thursday, three days after the attack. Police also said they believe the same group of people committed all the hold-ups. “We believe they are related,” said Officer Araz Alali, a department spokesman.

The first robbery occurred Monday a few minutes after 2 p.m. in the 1200 block of N Street NW, a block south of the Logan traffic circle. Alali said the victims — a man and his cousin — were walking when they were confronted by three men, two armed with handguns, another with a taser.

Alali said the victims tried to run but were caught. One was tased and the other was hit in the face, Alali said, adding that one victim had his wallet containing $300 and his iPhone stolen. One of the victims was treated at a hospital, Alali said.

About 4:30 p.m. the same day, about three blocks away, police said a man walking in the 1400 block of 10th Street NW was grabbed and pulled into an alley. Alali said the man was punched in the head by one man as a second man reached into his pocket and stole his wallet. Police said the victim reported the crime Thursday at 9:30 a.m.

A man walking in the 900 block of N Street NW about 5:20 a.m. Tuesday told police that a gray car slowed next to him and a man got out, shocked him with a taser and punched him. Another man got out of the car and took the victim’s wallet, cellphone and backpack, police said.

Alali said the victim was taken to a hospital to be treated.