Mark Harmon's Dog Attacked Crew Member on 'NCIS' Set

'NCIS' star Mark Harmon has a dog that attacked a crew member on set, but the dog has a pretty solid defense.

Sources connected with production tell TMZ, Harmon's dog is a 3-year-old pit bull mix that he rescued as a pup. His name is Dave.

Mark frequently brought Dave to the set, which was a dog-friendly environment. Other cast and crew members brought their dogs as well.

We're told a week ago one of the crew members was roughhousing with Dave ... something he did a lot, when the pooch became scared and attacked.

Our sources say the crew member needed 16 stitches to close the wounds, but returned to the set and is fine.