Research also indicates that there is extensive racial and ethnic discrimination by police and the judicial system. A substantial academic literature has compared police searches (showing that contraband is found at higher rates in whites who are stopped), bail decisions (showing that whites with the same bail decision as blacks commit more pre-trial violations), and sentencing (showing that blacks are more harshly sentenced by juries and judges than whites when the underlying facts and circumstances of the cases are similar), providing valid causal inferences of racial discrimination. Studies have documented patterns of racial discrimination, as well as patterns of police brutality and disregard for the constitutional rights of African-Americans, by police departments in various American cities, including Los Angeles, New York, Chicago and Philadelphia.