Rebecca Becky Triska was 15 and a sophomore at Ambridge High School when she vanished after an evening dance on September 19, 1958. Witnesses saw her leave the Workingman’s Beneficial Union dance around 11:30 p.m. and later saw her at about 11:45 p.m. at the Route 88 Drive-In Restaurant in Harmony Township, seated in a gold and white Plymouth with an unidentified older man.

Investigation attention turned to Frank Earl Senk Jr., then 25, whose car matched the description. A search of his vehicle found bloodstains and red hair; Senk said the blood was his and the hair belonged to nieces. He denied knowing Becky, refused a polygraph, and supplied an alibi corroborated by a companion. With no body and insufficient forensic proof at the time, Senk was held nine months and then released. Rebecca was legally declared dead in 1967; her body has never been found.

The case remains officially unsolved. Does anyone have information about Becky’s last known movements or memories of the Route 88 Drive-In that night?