The NCIS team investigated the recorded murder of an undercover ATF agent on the latest episode of "NCIS: Los Angeles."

In "Between the Lines," an ATF agent is shown being beaten up, and is then forced to identify himself and deliver threats to the other "rats" before being fatally shot on camera. The slain agent is ATF Agent Clark, an agent who was working undercover in a case involving sailors moving guns across the border.

Deeks (Eric Christian Olsen) finds another agent, Bower, who says Clark ruined a bust for him. Deeks begins to think that Bower wanted revenge for ratting him out. Clark's informant then tells them the Yakuza, a Japanese crime syndicate, are involved. But after he tries helping NCIS, he ends up dead.

Sam (LL Cool J) goes undercover as a sailor after a video is taken of the Yakuza boss taking ATF Agent Stone, who is the only other person who knows anything about Clark's case. The NCIS team tries to get Sam out of the situation after they find the body of Clark's informant, but Sam gets busted and is thrown into a room with Stone. Sam stays undercover, saying he's in the Navy.

Callen (Chris O'Donnell), Deeks and Bower set up a diversion, and Sam takes out a distracted guard and grabs his gun. Yet, when he gives Stone the gun, Stone turns the gun on him.

Stone is the real culprit, and his motive is money. But he doesn't know that Sam already took the bullets out of the gun before handing it to him. Callen, who came to Sam's rescue, has a second gun in his back pocket, and they take Stone into custody.

Meanwhile, in Afghanistan, Kensi (Daniela Ruah) is off looking for White Ghost when she gets captured in enemy territory.

On the next episode, "Zero Days," "While online during game play, Eric overhears his computer systems expert friend being attacked. Now it's up to NCIS to figure out if the computer system that manages the Russian missiles is at risk. A familiar face from Kensi's past shows up in Afghanistan."

Check out the promo below for "Zero Days," which airs Tuesday, March 25 at 9 p.m. EST on CBS.