D.C. police have arrested an Alexandria man suspected of sexually assaulting a taxi passenger on Saturday morning, and are continuing the search for assailants responsible for two other sexual assaults over the weekend.

The female passenger was in the cab with the driver and the driver's companion, Mohammed Suleiman Roble, 35, along the 2600 block of Georgia Avenue NW at about 4 a.m. Saturday. When she exited the cab, Roble followed and, after a short conversation, Roble dragged the woman into a nearby alley and physically and sexually assaulted her, police said.

The victim screamed for help, and officers responded to the scene and arrested Roble on charges of first-degree sexual assault.

Another sexual assault took place in the District a few hours earlier when a woman walking near 21st and H streets NE was approached by a group of males. One of the men grabbed the victim and pulled her to another location, where three males sexually assaulted her, police said.

One of the attackers was described as black, in his 20s, and not taller than 5 feet 5 inches. He had dreadlocks that were not quite shoulder length and was clean shaven. He was last seen wearing an orange hoodie.

A second attacker was described as a young black male with a bald head and a slim build. A detailed description of the third assailant was not available.

A third, separate sexual assault occurred on Sunday at about 3:45 a.m. in the 1900 block of Lincoln Road NE.

A woman answered her door to find someone who asked to use the telephone. Once the man entered the home, he sexually assaulted the woman, police said.

The attacker in that incident was described as a black male, about 5 feet 9 inches tall, with a dark complexion and short hair. He was clean shaven and was last seen wearing a black T-shirt and khaki pants.

Anyone with information can call police at 202-727-9099 or send a text message to 50411.