Investigators from three North Texas police departments are searching for a serial rapist who has attacked four alumnae of the same sorority.
All four of the victims are black women in their 50s and 60s who are members of Delta Sigma Theta and were alone in their homes when the attacks took place, police said.
Two women were assaulted in Plano, one in Coppell and one in Shady Shores.
The attacker indicated that he knew information about the victims, leading investigators to believe they are looking for one man in the four cases.
Sorority alumnae commonly have license plates and hats, jackets or shirts adorned in the sorority's red and white colors. Investigators have warned Deltas that they should not advertise their affiliation until the man is caught.
A person of interest was caught on camera following an attack in Plano in April. On Friday, Plano police released the surveillance video.
The man being sought by police is black and in his late 30s to mid-40s. He stands between 5 feet 7 inches tall and 6 feet tall and weighs between 250 and 300 pounds. He has a heavy build with a possible thin, well-trimmed beard. His hair is short, and he may be balding or have a receding hairline.
The two Delta Sigma Theta alumnae chapters in North Texas have circulated detailed with warnings about the attacks to their members.
Several Deltas have said they are shocked and angered by the attacks. They said they are primarily concerned about helping the victims as well as notifying members about the attacker. They declined to talk on camera and deferred to their national office, saying they were asked not to make public statements about the assaults.
The Delta Sigma Theta national office said it was aware of the attacks but has not released a public statement.
Anyone with information about the attacks or the man's identity is asked to contact the Plano Police Department Tip Line at 972-941-2148 or the Crime Stoppers Tip Line at 877-373-8477.
NBC 5's Randy McIlwain contributed to this report.