Episode 86 of "Without a Trace"
s04e16 The Little Things

As the team attempts to recover a 5-year-old boy who was in the back seat of the family SUV when it was carjacked, Danny begins to notice the tell-tale signs of Martin's prescription pain-killer addiction. The team initially explores if it was a botched carjacking or the plot of a kidnapper wanting to secure a hefty ransom from Ethan's affluent parents. However, they soon start to suspect Ethan's father, whom his wife and colleagues report has been acting odd lately, and who, per his wife's insistence, has been staying at a hotel for the past week. Upon further investigation, the agents find evidence that the father had been contacted by the kidnapper(s) and is foolishly attempting to handle the matter himself. Meanwhile, Danny catches on to the real reason why Martin is becoming excessively irritable and making rash on-the-job decisions.