Law & Order: Special Victims Unit: Season 9, Episode 9

Paternity

The murder of a young boy's nanny leads Detectives Benson and Stabler to suspect her Internet love interest, "Casanova" (Steven Bauer). However, the nanny's employers (played by Mark Valley and Anastasia Griffith) soon get troubles of their own when the father finds out that his son is not his biological son. Stabler's family suffers a tragedy leaving his unborn child in serious danger after Benson and Kathy are hurt in a car accident.