Woman is attacked on Esplanade

The woman, whose name and age was not released yesterday, told police she was walking near the footbridge at Massachusetts Avenue shortly after midnight when she was attacked by a black man with a shaved head and a muscular build, law enforcement officials said. The attacker wore a black tank top and black sweatpants. The woman said she was not sexually assaulted and called authorities with the cellphone of a passerby who arrived after the attack.

To avoid jeopardizing the investigation, authorities withheld details and the woman’s identity. But the incident has striking similarities to past assaults in the area committed by a man matching the description, said authorities. Local and state investigators are looking into whether yesterday’s assault and the past attacks are linked, said Jake Wark, spokesman for Suffolk District Attorney Daniel F. Conley.

“We don’t know if the most recent assault is connected to the earlier attacks, but each agency [State and local police] is investigating a possible connection between the most recent assault and the [2006 and 2007] cases,’’ he said.

Two attacks on the Esplanade in 2007 and an attack at Joe Moakley Park in South Boston in 2006 have raised the concern of authorities, who formed an investigative collaboration between Boston police, State Police, and sexual assault detectives assigned to Conley’s office.

In those cases, police released a sketch of a suspect, describing him as a black man, clean-shaven and bald, standing 5-foot-8 to 5-foot-10, of muscular build.

The man is suspected in a July 29, 2007, attack in which a 20-year-old woman was abducted at knifepoint on Beacon Street and forced to walk to the Esplanade. There, she was raped and robbed, at about 3:30 a.m. In another case, on June 16, 2007, a 20-year-old woman was jogging at the Esplanade near the Massachusetts Avenue shortly after 11 p.m. when she was raped.

The incidents match an attack on July 29, 2006, in which a 30-year-old woman was in the area of Joe Moakley Park at about 3 a.m. when she was raped.

Police are considering the time of the year, the locations and styles of the attack, and the description of the attacker in investigating the cases.

Yesterday’s attack stirred alarm among the walkers and joggers who flock to the Esplanade each day. In a city such as Boston, anyone walking at night needs to be mindful of their safety, they said, but no one thought such attacks could occur on the Esplanade, with its brightly lit pathway, even at nighttime, along the Charles River, surrounded by Storrow Drive traffic and Back Bay congestion.

“I would never think of that, especially right here,’’ said Valerie Levich, 20, from Somerville who sat reading a book after a bike ride on the pathway. She was waiting for her mother, who is considering moving into the area and would ride her bike on the pathway each day. “That kind of worries me,’’ Levich said.

Police would not say what the women in any of the attacks were doing at the Esplanade at night, whether they were walking home, or going to a job or local establishment. Pedestrians said anyone should be mindful of walking anywhere at night in a major metropolitan city, regardless of whether it is an open area such as the Esplanade.

“I could see why you would feel safe, but you can’t take your safety for granted,’’ said Ryan Duell, 25, who recently moved to the area from Nebraska with his wife, Jill, and joined her for a run yesterday on the pathway.

Milton Valencia can be reached at mvalencia@globe.com.