Detective Douglas Grozen was a corrupt Los Angeles Police Department detective.
He along with a group of SEALs and his own partner went to the house of a local drug kingpin and stole a large sum of money before disappearing. Grozen killed his own partner before fleeing the scene.
He later returned to the scene where he had a confrontation with former Navy SEAL and NCIS Special Agent Sam Hanna.
Pretending to be grief-stricken, Grozen threatened to get the media involved unless NCIS fully corporated with his investigation and Sam gave the Detective the names of all those involved in the raid.
OSP later took Navy SEAL Morris Raspen into custody where he told Agent G. Callen of what had happened at the drug deal while also stating that Grozen was a dirty cop.
After some "help" from Sam in the form of a threat and that Raspen would have to live with the blood of two murdered SEALs on his conscience, the team arranged a plan to get Grozen to confess to the killings and held a meeting at a local golf course.
In the ensuring gunfight, Grozen shot Raspen and attempted to hit Callen but Sam who had been hiding underwater, ambushed Grozen and shot him in the chest, resulting in the corrupt cop's death.
Grozen is a corrupt cop with little or no regard for human life which is first seen when he ruthlessly guns down his partner during the raid on the drug dealer's house. He is also a cold-blooded killer, willing to kill anyone just to cover his tracks and has no remorse for his actions, strongly suggesting he is either a psychopath or a sociopath. He is only driven by greed and the desire for money.
- Rod Rowland who played Douglas Grozen would later go on to appear in the original NCIS series in the Season 11 episode, Oil and Water (episode).