'NCIS: LA' season 8 episode 10 spoilers: NCIS team gets new lead on their mole investigation; Chris O'Donnell hints more Callen-Garrison scenes

NCIS gets a new lead in the ongoing mole investigation on the upcoming episode of "NCIS: Los Angeles" season 8.
Titled "Sirens," next week's episode will see the team get one step closer to uncovering the real identity of the mole. According to the official synopsis for episode 10, an unknown female assailant kills two men disguised as Sherriff's deputies in front of Callen's (Chris O'Donnell) house. This serves as a new lead for the NCIS team's ongoing investigation to find the mole. Meanwhile, Nell (Renée Felice Smith) comes to visit a prison to interview an inmate who is withholding information regarding the department's leak.
This week's episode saw Callen finally began to get some answers that he has been searching for his entire life, when his father Garrison (Daniel J. Travanti) made an unexpected appearance. Speaking with TV Guide, O'Donnell shared hints on how Callen's reconciliation with his father will affect the story. "I know we're going to see more of Garrison this season," he revealed. "We haven't really gotten into it yet. I know that for part of the time, he is still hanging around Los Angeles, and so there is interaction [between them], but we haven't explored that completely."
As for the team's mole investigation, it seems that they are getting closer to finding out the mole. O'Donnell obviously can't give clues on the mole's identity, but he gave teasers about the major story arc of season 8. According to the actor, he already read scripts for the two episodes featuring the mole investigation.
"... It's really well-done. The script for the second one may be one of the best scripts we've had," he said. "It's really clever the way they did it, and it's not fully resolved yet, but we are starting to get a peek at who the mole may actually be. And I think it'll be shocking for the fans. ... There's some twists and turns that you really did not see coming."
"NCIS: Los Angeles" season 8 airs every Sunday night at 8 p.m. ET on CBS.