PRINCE GEORGE'S COUNTY, Md. -- Police in Maryland said they are concerned that a man who meets women on the Internet and then rapes them will strike again.

Police said the man used Craigslist personal ads to meet and sexually assault several women.

Authorities said the man has raped at least six women.

Investigators said the man meets women through the online classifieds site, sets up a meeting and then rapes them, police said.

The attacker usually wears a ski mask and is armed with a handgun, police said.

Investigators said the victims were attacked inside different buildings in Temple Hills and Suitland.

The most recent incident happened on Tuesday. Police said they were called to the 9100 block of Baltimore Avenue in College Park by a woman who said she had been sexually assaulted.

Investigators said the woman told them she met a man online and agreed to meet at an apartment in Suitland.

When the woman arrived at the apartment building, a man was waiting in the hallway, police said.

The woman said she was raped at gunpoint, and afterward the man fled, according to police.

The investigation is ongoing.