MIAMI (AP) _ The late 1990s in Miami was marked by high violent crime rates, with roving gangs that stalked tourists, but prosecutors say the violence also included acts committed by the police.

Based on information from two retired officers who pleaded guilty to conspiracy in September 2001, 11 other officers were indicted on federal corruption charges alleging cover-ups in four police shootings in which three men were killed.

The 11 were scheduled to go on trial Monday on charges of planting guns, manipulating evidence or covering up crimes by others in a series of questionable shootings. The two who pleaded guilty are slated as the prosecution's star witnesses.

The case was the city's worst police scandal since the 1980s, when the so-called ``Miami River Cops'' stole cocaine from drug traffickers and sold the drug themselves. More than 100 officers were arrested, fired or disciplined in that case.

``The history of Miami has been characterized by ugly police-community relations,'' said Howard Simon, executive director of the American Civil Liberties Union of Florida. ``There is a loss of confidence, if not outright hostility, by the minority community because of the great number of shootings of typically unarmed black young men.''

Miami is not alone.

In Los Angeles, about 100 criminal cases were overturned after investigators heard allegations of police abuses in the police department's Rampart Division that included evidence tampering, unjustified shootings and thefts.

The numbers of police shootings in New York City have declined markedly but have been highlighted by cases such as the 1999 death of immigrant Amadou Diallo, shot 19 times by four white officers when he reached for his wallet.

The four Miami shootings involved the deaths of three black men and the wounding of a fourth, plus one in which a man escaped injury.

In all of the cases, prosecutors say, guns were planted to make it look as if the three robbery suspects, a drug suspect and a homeless man were armed.

An attorney for two of the indicted officers said the shootings were justified.

``The justifiable use of force and deadly force laws have been in existence for years,'' said attorney Richard Sharpstein. ``All of these shootings were well within those parameters.''

The federal trial is expected to last three to five months. No state charges were filed.

In the past, police killings in Miami have intensified already strained race relations in a city beset by political corruption, economic woes and other problems. The deaths of black and Hispanic men and the subsequent acquittals of officers triggered riots or smaller street clashes six times from 1980 to 1995.

Voters have approved a civilian oversight board for the police and members are about to be named.

Police Chief Raul Martinez created stricter procedures for the use of deadly force by officers, allowing them to fire their weapons only when facing an imminent deadly threat, but some community leaders said he didn't go far enough.

Martinez quit in November and former Philadelphia Police Commissioner John Timoney took over the department.

Brad Brown, president of the Miami-Dade County chapter of the NAACP, blames the shootings on a mentality among some officers that they're above the law.

``Once you start stepping over the line on what's acceptable, it's only a little bit further and they become involved in the criminality themselves,'' Brown said.