Harper was last seen in Rantoul, Illinois on March 10, 2007. She left her mother's Paxton, Illinois home on March 9 to go to a party in the 1300 block of Laurel Drive in Rantoul with a male companion. Harper left the gathering early on the morning of March 10. She never arrived home and has never been heard from again. Her mother reported her as a missing person the following week. She waited because Harper had previously failed to return for several days at a time. Harper was carrying a black handbag at the time of her disappearance. All her other possessions, including her medication, were left behind.

After Harper's disappearance, an anonymous caller told police she had died of an overdose and her body was in an area of Paxton known as Dogtown. Dogtown contains three gravel pits and has been the site of many missing persons searches over the years, but no evidence relating to Harper's case was found there and the tip has not been verified.

Another young woman, Heather Zimmerman, disappeared from the Rantoul area in 1997. Authorities stated there were similarities between the two cases, and they had also searched for Zimmerman in the Dogtown area. They have the same person of interest in both cases; he has not been publicly identified. The disappearances have not been conclusively connected, however. The friend Harper went to the party with is not being called a suspect in her disappearance.

Authorities believe Harper disappeared under suspicious circumstances. Both Paxton and Rantoul police are investigating.