The 22-year-old was pregnant and living with her husband Charles Cann II and their 15-month-old son in Huntington Mills, Luzerne County, according to authorities and the Charley Project.
Ilonka was last seen alive on the morning of May 26, 1970, troopers said. Charles told police he said goodbye and went to work at the Berwick Junior High School around 7:20 a.m.
When he returned home around 3:30 p.m., he found their son alone, crying in his crib upstairs, investigators said. Ilonka was nowhere to be found.
He reported her missing the next day and an "extensive" search ensued, with dive teams dispatched to check a nearby pond, but no trace of the pregnant mom ever turned up.
State police drained that pond last summer as part of the investigation into Cann's disappearance, Fox56 reported, but authorities have not said if the effort turned up any evidence.
Anyone with information is asked to call troopers in Wilkes-Barre at 570-822-5400 or submit an anonymous tip through Crimewatch.
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