Robert Pratt, 27, pleaded guilty to attempted assault of a real estate agent at a model home in Cary last September. He is serving a 10-15 year sentence.
Friday, Durham police filed new charges for a similar attack in August.
"We are looking at Mr. Pratt at this time as a suspect in one or more cases in or around Duke University," Duke Police Capt. Charles Nordan said.
One Duke police case that remains open is the September 1995 rape of a woman in Duke Forest. Right after the attack, a 19-year-old Duke hospital employee was accused, but later cleared when his fingerprints and DNA did not match the suspect's. At that time, his family talked about their relief.
Kathleen Pearson, mother of the former suspect, said her son was in the "wrong place, at the wrong time. The impossible happened, and we are ready to move on."
Investigators are moving on as well. Late Friday, a search warrant was filed in Orange County asking for Pratt's fingerprints and a blood sample. Duke police are now comparing notes with several agencies.
"We have been assisted by the SBI in looking at Mr. Pratt for some of those crimes," Nordan said.
Wake County District Attorney Colon Willoughby also says that Pratt is a possible suspect in a vicious attack on a woman in May of 1997 at Falls Lake.