A new study from the University of Chicago has found police in America’s biggest cities are failing to meet even the most basic international human rights standards governing the use of lethal force.

The cities were graded using a system developed from international human rights law and standards on police lethal use of force.

America’s biggest police forces lack legality, the study finds, because they are not answerable to human rights compliant laws authorizing the use of lethal force.

Flores, also a leading expert on immigration policy and human rights said, “Police departments grant their officers deadly discretion, allowing the use of lethal force to capture an escaping suspect or to prevent the commission of a felony, regardless of whether the suspect poses a threat of any kind.”

The report recommends Congress, state legislatures and police departments take substantial and immediate steps to bring police use of force policies into compliance with human rights standards.