He claims Dugan, 48, beat an Iraqi civilian suspected of terrorism, threw him handcuffed and hooded from a vehicle, and dragged him across rocks.
Nakhla's accuser, Wissam Abdullateff Sa'eed Al-Quraishi, 37, of Amman, Jordan claims that Nakhla held Al-Quraishi down while a coconspirator poured feces on him.
Al-Quraishi also claims Nakhla and others stripped Al-Quraishi and other prisoners naked and piled them atop one another, separated by boxes.
Al-Quraishi also claims he watched Nakhla hold down a 14-year-old boy while an unidentified coconspirator sodomized the boy with a toothbrush.
Sa'adoon Ali Hameed Al-Ogaidi, a 36-year-old Arabic teacher from Baghdad, claims he was beaten by Johnson, threatened with execution and stripped naked and paraded before other prisoners.
Mohammed Abdwaihed Towfek Al-Taee of Baghdad claims an unidentified L-3 translator forced him to consume so much water that he vomited blood several times and then fainted. He claims the translator and others later tied a plastic line around his penis, preventing urination, and made him drink more, nearly killing him.
Burke and her associates filed a similar federal lawsuit in May in Los Angeles, claiming L-3 and CACI employees, including former CACI interrogator Steven Stefanowicz, abused an Abu Ghraib detainee named Emad al-Janabi.
All five cases stem from a District of Columbia federal judge's refusal to grant class-action certification to a 2004 lawsuit brought by the same attorneys and 237 plaintiffs. That complaint, which is still pending, consolidated two cases that originally named Stefanowicz, Nakhla, Dugan and Johnson. They were dismissed as defendants in the original cases for lack of jurisdiction.
Burke said more workers may be sued, and more plaintiffs may be added to the existing lawsuits.
Trying multiple cases has less potential impact than a class-action lawsuit, partly because individual plaintiffs have less clout, said Herman Schwartz, a law professor at American University in Washington. Also, individual plaintiffs may be inclined to settle for less money than a large group, he said.
Associated Press writers Stephen Manning in Montgomery Village, Md., and Dan Catchpole in Seattle contributed to this report.