According to numerous conflicting reports, the shooting started after a small car had mistakenly failed to comply with an Iraqi police officer's call to stop, the Blackwater guards then fired on the car, possibly believing it to be a suicide bomber.

The suit was filed on behalf of a number of Iraqi citizens by the Center for Constitutional Rights and a number of other lawyers alleging that Blackwater had violated US and international law, as well as participating in war crimes and violation of the Racketeer Influenced and Corrupt Organization Act.

According to the complaint, Blackwater had “created and fostered a culture of lawlessness amongst its employees, encouraging them to act in the company’s financial interests at the expense of innocent human life” and that Blackwater deployed "shooters" in Baghdad knowing that some were using steroids or other psychoactive substances.

Plaintiffs also moved to include a claim that Blackwater intentionally destroyed evidence by repainting the vehicles involved in the Nisoor Square massacre and by shredding documents pertaining to the company’s criminal and civil legal exposures.

November 27, 2007: An amended complaint was filed, adding the families of two other victims, as well as adding the additional charge that Blackwater routinely deploys heavily armed "shooters" in the streets of Baghdad with the knowledge that up to 25 percent of them are chemically influenced by steroids or other judgment-altering substances, and fails to take effective steps to stop and test for drug use.