Boston-area law enforcement officials are investigating the assault and robbery of a woman on the Charles River Esplanade early this morning.

Suffolk County District Attorney Daniel F. Conley, Massachusetts State Police Colonel Mark F. Delaney, and Boston Police Commissioner Edward Davis urged caution in the area and reminded pedestrians to remain alert and aware of their surroundings, especially in isolated areas, as summer weather returns to the Boston area.

The victim in this morning’s case was assaulted and robbed as she was on foot alone near the Massachusetts Avenue footbridge shortly after midnight. State Police assigned to the Boston Barracks responded to the scene and spoke to the woman, who had called 911 from a Good Samaritan’s cellular phone. The woman reported to first responders that she had not been sexually assaulted.

The woman described her assailant as a bald African-American male in his 30s with a muscular build. He was wearing a black tank top and black sweatpants.

At this point, to protect the integrity of the active investigation, police and prosecutors are not providing further information about this morning’s victim or specific details about the attack.

Suffolk prosecutors, State troopers, and Boston Police detectives have not linked this morning’s assault to prior attacks on the Esplanade during the summer of 2007 and in South Boston in the summer of 2006. The three agencies are jointly investigating a possible connection to the three unsolved cases, however. Those cases are:

1. A July 29, 2007, incident in which a 20-year-old woman was abducted at knifepoint on Beacon Street and forced to walk to the Esplanade, where she was raped and robbed at about 3:30 a.m.

2. A June 16, 2007, incident in which a different 20-year-old woman was jogging at the Charles River Esplanade on a footpath near the Massachusetts Avenue bridge shortly after 11:00 p.m. when she was raped.

3. A July 29, 2006, incident in which a 30-year-old woman was in the area of Joe Moakley Park when she was raped at about 3:00 a.m.

Each of those victims described her assailant as a clean-shaven African-American male in his mid-20s to mid-30s, standing 5’8” to 5’10”. At the time of the attacks, he had a medium to large build and a bald head.

Anyone with knowledge of the crimes or the suspect, or who was present near the Esplanade, Dartmouth Street, or Moakley Park areas at the times noted above, is urged to contact the Massachusetts State Police Barracks in Boston at 617-727-6780, call the toll-free Boston Police CrimeStoppers tip line at 1-800-494-TIPS, or text the word “tip” to CRIME (27463).