Sandy-haired and always smiling, Deeks is the last person NCIS: Los Angeles fans would expect to have a dark side. From killing cops to waterboarding old men, the detective has proved them wrong.

As fans await season 8, one questions remains: now that Deeks life is on track, will his violent side stay tamped down? According to Eric Christian Olsen, his character ditched his anything-goes nature after one dark day in Afghanistan.

"This character shot his dad; his dad was wielding a shotgun and was abusive to his mother. This character killed a cop in defense of a girl," Olsen told fans at MCM London. "This character obviously has issues of violence solving violence, especially when it comes to women that he cares about."

For fans, it feels like these outbursts have permeated Deeks' entire tenure with the Office of Special Projects. Despite this, shooting his father and murdering that cop took place years in the past, and, ever since season 5, Marty has managed to keep his cool. His brief yet terrifying experimentation with waterboarding seems to have stopped him cold.

The character bailed on the torture, obviously, and that's when he broke down in tears and just held on to [the victim] because he lost himself in it," Olsen said of "Spoils of War." "The way that I play that is that's the moment that he becomes his father - because his father was that abusive to his mother - and he realizes that's who he's become. So it's more about his own fear of becoming the monster that he hates the most."

Do you think another threat to Kensi's (Daniela Ruah) life would push Deeks back to the dark side, or has he discarded those urges entirely? Sound off in the poll below!

NCIS: LA will return to CBS this fall, now airing Sundays at 10 p.m. ET.