Rumor has it that Pauley Perrette, who will be leaving NCIS in May decided to do so because of Mark Harmon's dog.
Harmon rescued a pitbull a few years ago and frequently brings him on set.
The pitbull attacked a crew member last year which resulted in him getting 16 stitches, but in the end the crew member was blamed for "playing rough" with the dog.
Perrerre felt that after the incident, someone else might get hurt by the dog and shared her concerned with the show bosses, but they sided with Harmon, who is also a producer on the show. So she decided to leave the show.
Perrette said her statement when her leaving the show was announced that she decided to leave the show last year, which fits with the timeline of the dog attack.
Perrette would have left last season if producers didn't agree to her terms. She told her bosses that she wouldn't be on set with the dog around since she felt anxious around it around so they separated her and Harmon. They haven't shared a single scene this entire season so far and haven't been on set at the same time.