Associated Press

The owner of the pizza shop where the Columbine gunmen worked has been added as a defendant in four lawsuits filed by the families of students wounded in the shootings.

The amended complaints, made public Thursday, accuse Robert Kirgis of allowing a work environment that included discussions of killing and the use of drugs and alcohol. The shop was where gunmen Eric Harris and Dylan Klebold met Philip Duran, who introduced them to Mark Manes, who sold them a weapon.

Klebold and Harris killed 12 students, a teacher and themselves at Columbine High School on April 20, 1999.

The changes made in lawsuits filed by the families of wounded students Richard Castaldo, Lance Kirklin, Mark Taylor and Sean Graves were among the first since the Jefferson County sheriff's office released 11,000 pages of files from the case last month to comply with a court order.

Also added as defendants were James Royce Washington and Ronald F. Hartmann, operators of a gun-show booth where Harris and Klebold bought some of their weapons, and the Tanner Gun Show.

The families of six slain students amended their joint lawsuit to allege that the sheriff's office has kept material from the plaintiffs, including crime scene photos and information that could identify other possible defendants in the department.

Relatives of slain students Daniel Rohrbough, Kelly Fleming, Matt Kechter, Lauren Townsend, Kyle Velasquez and Cassie Bernall also added Hartmann as a defendant.

The lawsuits already listed Sheriff John Stone, Columbine Principal Frank DeAngelis, the gunmen's parents, and other school and sheriff's office employees as defendants.

Also listed previously was Neil Gardner, a sheriff's deputy who was not wearing his prescription eyeglasses when he traded gunshots with the gunmen.