The Navy Yard Bombing was an incident that occurred in May 2012 when businessman/terrorist Harper Dearing attacked NCIS by detonating a bomb strapped underneath the car of NCIS Director Leon Vance in revenge for the death of Dearing's son, Evan who had perished in an attack on the U.S.S. Brandywine.
The attack left many buildings in the NCIS area damaged and also killed an unknown number of NCIS personnel including Ed Girard, the father of Max Girard while NCIS Special Agent Timothy McGee was among those injured in the blast but ultimately survived.
After months of dead ends, NCIS Special Agent Leroy Jethro Gibbs approached Dearing alone and just before Dearing could shoot him, Gibbs stabbed the other man, killing Dearing while ending his threat to NCIS and avenging the people who had died in the attack.