Amidst personal reasons, "NCIS" season 14 star, Mark Harmon is now planning to quit working on this hit TV series. There were rounding speculations that he has been locked in a family feud and that it was due to his sister named Kristin. Apparently, their problem is caused by their vicious custody battle over their son Sam for more than 30 years.

As per Asia Starz, Harmon claimed that his sister Kristin is not fit to become the mother of Sam. He even added that his sister has been hooked to drugs during the time that Sam's father, Rickey Nelson, died in a plane crash on 1985.

It was also indicated that Nelson was already divorced with Kristin just three years before the incident happened. Unfortunately, Sam's father was also a drug addict who was hooked to cocaine as well and which was the culprit of the crash.

On the recent news, Harmon, together with his wife Pam Dawber, already seek for a permanent custody over Sam when he was still 12 years old. It was even revealed that Sam was even afraid of his own mother when the woman acted erratic in the past.

It was in 1987 when Kristin was brought to the rehab for an addiction over a painkiller. However, in an insider report, Harmon and his sister tried to keep bygones be bygones. On the other hand, Dawber, wife of the "NCIS" actor even testified that Kristin also blasted while having shopping and even said that her son was already afraid going home, Radar Online reported.

On the other hand, Kristin's lawyer also accused Dawber of using cocaine while working on ABC during the sitcom run in the year 1978 to 1982. Eventually, the accusations were denied by Dawber and suddenly, Harmon dropped the suit.

Meanwhile, "NCIS" Season 14, Episode 19 will feature how Agent Gibbs, played by Harmon, will deal with the case which involves the Marine. He will also explain why Vietnam War veteran, Henry Rogers played by the Bruce McGill is a grumpy and hard witness, CaterMatt reported.