How to follow strangers (2013)

There is a true story of a woman who died in her apartment and it took people a year to find her body decomposing in a crisp Chanel suit. A young man becomes obsessed with this urban tragedy and disappears, wondering if anyone will notice. A young woman who shares his commuting schedule DOES notice. And when he resurfaces, she decides to follow him setting of a chain of events that bind them together...