Dead Line(2007)

Original title: Interferencia

Martin Sanders (Andres Bagg), a socially awkward recluse whose only entertainment comes from eavesdropping on other people's private conversations, gets a shock when he overhears the devilish plottings of a serial killer who lives in his building. Now, Martin knows the killer's voice -- but can he discern the murderer's face from a sea of strangers before he claims another victim? Virginia Lustig and Chris Longo co-star.