Very similar to the episode "Pied Piper" from the series Lie to Me Season 2 Episode 19 aired Aug 16, 2010. In both episodes, the unsub called the parents before abducting their children, leaving a creepy message in a child's voice behind, which ends with "I'm gonna get you!"
The abducted boy's mother, Lida Taffert, is said to be Polish. The actress who plays her, Marika Dominczyk, was actually born in Poland.