A bomb explodes at a Marine event in Venice Beach. The bomb was made of military grade explosives, HMX.
A journalist reports that the JLF is responsible and other news stations pick that up. Agents monitoring the JLF in LA say the organization has been dormant for a year and they aren't responsible.
The journalist gives NCIS a false source, so they follow her to a mall where she meets with a man. He gets angry and stabs her dead. Sam and Callen capture him and he takes responsibility for the bombing.
He's from Sudan and had been campaigning private and public organizations for more funding for his homeland. After his family was killed there, he set up the bombing to force the US to send troops to Sudan and end the conflict there.
NCIS stops the additional two bombs from going off.