Police said they have questioned several men in a series of attacks on members of a national black sorority but have ruled them out.
A man has attacked at least four members of Delta Sigma Theta in home-invasion-style attacks since November 2010, sexually assaulting three of them. Women in Plano, Coppell and Shady Shores have been attacked.
Police last week released a police sketch of the man and earlier released surveillance video of the man.
Investigators said they have received several tips and leads about men who fit the man's description.
Police questioned the men and took DNA samples from them, but none of the men tested so far have matched the man's DNA.
Investigators collected DNA evidence from each scene and have a DNA profile of the man they are looking for in the attacks.
"America's Most Wanted" profiled the case on an episode last week.
NBC 5's Randy McIlwain contributed to this report.