Norwalk police are looking to social media for help solving a 31-year-old case involving a kidnapping and possible killing.

"It's not a who-done-it," says Gina Grisanti, whose sister April was last seen at a Main Street bar on Feb. 1, 1985. "We know who did it. We need the proof. We need someone to come forward."

Police say April Grisanti was attacked by her ex-boyfriend, James "Purple" Aaron, hours before her disappearance -- but she declined to press charges.

Later that evening, police say Grisanti left the bar when Aaron showed up. Witnesses told them they saw her use a pay phone, but Aaron followed her, forced her into a blue Cadillac, and drove north on Main Street toward New Canaan Avenue.

Aaron was later convicted of kidnapping Grisanti and served more than five years in prison, but police and the family say they believe he also killed her.

Complicating more serious charges, investigators never found her body. 

Lt. Art Weisgerber of the Cold Case Unit shared the case on the department's Facebook page.

"We're trying to start to use social media, put the cases out there, people can look at it, share it with their friends," he says. It's the second cold case posted on the department's page in the past week.

Police and Grisanti's family members say they hope social media attention will generate leads to where her body might be found.