Law & Order: Criminal Intent (2001)

S3E9 Happy Family

The brutal murder of a wealthy family’s patriarch sparks an investigation filled with potential suspects, each harboring their own reasons for wanting him dead. These include his soon-to-be ex-wife, an ex-con friend of hers, the children's nanny, the victim's doctor brother-in-law, and even the eldest son. Detectives Goren and Carver decide to bring all the family members together to untangle the web of deceit and motives in a tense family court setting.