Portland police are asking the public to help identify a man believed responsible for three similar assaults in the area of Congress Street between Neal and Weymouth streets.

The assaults occurred on April 20 and 30, and May 24, and in each case, a man grabbed a woman from behind.

In the first case, a woman reported to police that on April 20 she was walking on Congress Street when a man grabbed her buttocks. She sprayed him with pepper spray and he ran off. That assault was not reported until May 27.

Then on April 30 around 9 p.m., a 29-year-old homeless woman reported that a man assaulted her from behind in an alley at 169 Neal St. The assailant grabbed the woman’s neck, stole the money she had concealed in her bra and then fled.

In the May 24 case, a 30-year-old Portland woman said a man approached her from behind at about 11:30 p.m. near Weymouth and Congress streets, grabbed her around her neck and took her bra.

In each instance, the description of the assailant was similar – a white man about 30 years old, 5 feet 7 inches to 6 feet tall, with long blond hair, a heavyset, rugged frame, two or more lower lip piercings, and wearing a baseball cap and glasses.

“We have a pretty unique description involved here, which is part of the reason we want to get this out to the public,” said Assistant Police Chief Vern Malloch.

Investigators believe the man either lives nearby or frequents the area where the assaults took place, but despite stepping up patrols, they have not located a suspect.

Malloch urged women to be more aware of their surroundings while out at night, and to avoid walking alone for long periods if possible. Women should also keep a cellphone handy and be ready to call 911 if attacked.

“Be sure to know that you should run or fight or scream to defend yourself in these types of attacks,” Malloch said. “These are all very important things that may seem simple but it’s worth saying and we think it’s worth people being aware of.”

Anyone with information about the assaults or who knows someone matching the suspect’s description is asked to call Portland police at 874-8575.

To provide information anonymously:

• Mobile phone users can text the keyword “GOTCHA” plus their message to 274637 (CRIMES).

• Submit a tip by going to the Portland Police Department website and clicking “Submit an Anonymous Crime Tip.”

• Anonymous phone tips can be left on the department’s Crime Tip line at 874-8584.