Police are looking for a serial rapist who may be targeting sorority alumnae in at least three North Texas cities, where at least four women have been attacked in their homes by a man who reportedly claimed he knew personal details about his victims.

The victims, all members of the predominantly black Delta Sigma Theta sorority, were in their mid-50s to mid-60s and all were attacked late at night in their homes, according to police. It is unclear if the women knew each other.

The attacks took place in the northern Texas cities of Plano, Coppell and Corinth, which are all within 40 miles of Dallas. The most recent assault occurred Friday night. The first attack occurred in November 2010.

During each incident, the assailant revealed that he knew personal information about his victims.

In its most recent statement on the attacks released Monday, the Delta Sigma Theta sorority's national headquarters urged its Dallas-area members to take a variety of safety steps. They include removing sorority gear from their vehicles, homes and offices, and not wearing any clothes or accessories that may identify them with the group.

Members were also advised to avoid being alone or posting information about their day-to-day activities on social networking sites.

The suspect, who police believe to have caught on a surveillance video, is described as a black male, in his late 30s to mid-40s, who may be up to six feet tall and weigh as much as 300 lbs. He may have a thin, trimmed beard with a short haircut, possibly with a receding hairline.

"To think that our members are being targeted is disturbing and extremely disheartening," said Cynthia M. A. Butler-McIntyre, the sorority's national president, in the statement. "Until the individual responsible for these crimes is brought to justice, we will continue to remain in close communication with one another and law enforcement officials in the respective jurisdictions."

Plano police are asking anyone with information about the case to call 927-941-2148 or the Colin County Crime Stoppers at 877-373-8477.

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Newscore contributed to this report.