BOULDER, Col. -- Boulder police are warning women about not walking alone at night after a 21-year-old woman said she was attacked and nearly strangled early Friday morning.

The attack was just the latest in a series of assaults -- sexual and physical -- reported in Boulder. Four other November assaults remain unsolved.

The woman said she was walking home from a friend's house when someone came up from behind her, pushed her to the ground, climbed on top of her and began strangling her, Police Chief Mark Beckner said.

She kneed the man several times in the groin, she said, and that's when he let go of her neck, allowing her to escape. She ran to a friend's home for help, police said.

The alleged assault occurred between 12:30 a.m. and 1 a.m. in an alley to the west of 12th Street, between College and Euclid avenue.

She has described her attacker as a Hispanic man between 5 feet 7 inches tall to 5 feet 10 inches tall. He was 35 to 40 years old and had a thin build, she said. She believed he was wearing a dark hooded sweatshirt and jeans.

This case remains under investigation, as do the other recent assaults that have been reported to the police department, Beckner said.

The police department would like to encourage community members to take the following precautions:

Walk in pairs or groups, particularly after dark. Use the buddy system. Do not leave a friend alone in a public or potentially unsafe place.

Use well-lit pathways and busy streets as much as possible.

Be aware of your surroundings and people in your immediate vicinity.

Consider carrying whistles or other noise-making devices so that you could draw attention to yourself, if necessary. Carry a cell phone, if possible, so you can summons help.

Keep an eye out for anything unusual and notify police immediately of anything that seems suspicious. Trust your instincts.

Do not consume alcoholic beverages to the extent that you are unable to care for or defend yourself.

Please report crimes that occur to you or people you know and report them as promptly as possible.

Anyone with information about this suspect or this crime is asked to contact Detective Jane Harmer at 303-441-3330 Monday through Friday from 8 a.m. to 5 p.m.

After hours, please call the non-emergency dispatch line at 303-441-3333.

Those with information who wish to remain anonymous should contact the Northern Colorado Crime Stoppers at 1-800-222-TIPS (8477) or 1-800-444-3776. Tips can also be submitted via the Crime Stoppers Web site at CrimesHurt.com.

Those submitting tips through Crime Stoppers that lead to the arrest and filing of charges on a suspect(s) may be eligible for a cash reward of up to $1,000 from Crime Stoppers.