SAN DIEGO -- A federal lawsuit filed in San Diego claims an intoxicated employee of a private security agency randomly murdered an Iraqi vice president's guard after a 2006 Christmas Eve party and the company tried to cover it up.

The suit alleges that former Blackwater employee Andrew Moonen fatally shot Raheem Khalaf Sa'adoon, 32, who was a security guard for Iraqi Vice President Adel Abdul Mahdi, and that several Blackwater-related defendants under the control of company Chairman Erik Prince attempted to evade responsibility.

The lawsuit was filed Thursday on behalf of Sa'adoon's widow, Wijdan Mohsin Saed, and their two sons, 11-year-old Sajjad Raheem Khalaf and 8-year-old Ali Raheem Khalaf.

According to the complaint, Moonen left the holiday party and lost his way in a section of Baghdad known as Little Venice.

Visibly intoxicated, he encountered Sa'adoon on guard duty and fired his company-issued firearm at the victim, killing him for no reason, the lawsuit alleges.

Blackwater -- now known as Xe -- is also accused of spiriting Moonen out of Iraq, bribing an Iraqi government official and destroying documents and other evidence relating to the shooting and other Blackwater shootings, according to the lawsuit.

Blackwater USA was formed in 1990 to provide training support to military and law enforcement organizations.

The company runs the U.S. Training Center Southwest in Otay Mesa in southern San Diego County.