BOSTON -- Sexual attacks on three women in Boston that happened during the past year have been linked by DNA, the Boston Police Department announced Wednesday.

Detectives said all three attacks, which began in August 2007, ended with the victims being taken to Charlestown and sexually assaulted after being picked up in other parts of the city.

The latest incident happened on Aug. 5. Police said a woman was assaulted in the early morning hours near Boylston and Arlington streets when she accepted a ride from a man.

The man drove her to the Terminal Street area of Charlestown and assaulted her, police said. After a struggle, the man fled the area.

Last fall, another woman was assaulted in Charlestown on Nov. 22, 2007, during the early morning hours after being picked up near State Street in the financial district.

On Aug. 8, 2007, a woman said that she accepted a ride from a man near Stuart Street. She said that he later assaulted her, also in the Terminal Street area of Charlestown.

Anyone with information about the assaults was urged to call the Sexual Assault Unit 617-343-4400.