Updated, 6:12 p.m. | A Queens man was arrested on Tuesday in connection with at least one in a string of 20 sexual assaults in various Brooklyn neighborhoods dating back to March, the police said.
Plainclothes police officers stopped the man, Joshua Flecha, 32, on Greenwood Avenue in Brooklyn, between East Fourth and Fifth Streets, around 3:15 a.m. because they suspected he might be attempting to break into a parked vehicle, according to Paul J. Browne, a spokesman for the New York Police Department.
Officers discovered Mr. Flecha holding a cellphone that was playing a pornographic video; his fly was unzipped and he had marijuana in his possession, Mr. Browne said.
A victim of an attack in May later picked Mr. Flecha out of a lineup for a sexual assault committed at the entrance to the Seventh Avenue F train. In that case, the assailant grabbed her breast and then exposed himself and masturbated in front of her, according to the spokesman.
Detectives have included several crimes in the pattern and said that several suspects could be responsible for waves of assaults within the overall grouping. Additional lineups were being conducted Tuesday.
Mr. Flecha was the second suspect picked up by the police in connection with the sexual assault pattern, which involves the groping and grabbing of young women in and near subway stations in Bay Ridge, Sunset Park and Park Slope. The pattern also includes one rape.
The first suspect, Adolfo Martinez, 26, of Sunset Park was arrested last week and charged with forcible touching and sexual abuse stemming from an episode on Oct. 10; Mr. Martinez has admitted to similar acts but said he could not recall where they had occurred.
In a separate spate of attacks in Queens, the authorities might have gotten a break on a series of groping incidents involving a man on a black mountain bicycle who has been riding up to victims and grabbing heir buttocks or breasts, the police said.
Six such sexual assaults have occurred in the last two months in the Woodside and Sunnyside neighborhoods.
Tuesday morning, a man on a bicycle drew up alongside a woman walking on Roosevelt Avenue at 31st Street, the police said. She screamed and the man pedaled away. Nearby officers responded and caught the man two blocks later, but when they returned to the scene, the woman was gone, the police said. The bicycle the man was riding was covered with silver tape, but underneath it the bike was black, the police said.
The police said they were questioning the man and arranging lineups for other bicycle groping victims. No charges have been made.