Final appearance of Megan (Kim Delaney). Kim Delaney's exit from the show was due to a lack of on-screen chemistry between her and David Caruso. The show runners used a so-called "trap-door" plot line, in which her character's letter to Horatio implied that she had returned to work too soon after having witnessed her husband's murder, and was still grieving the loss, therefore was unable to handle the rigors of the job anymore as head of the crime lab and was passing the torch to Horatio.