A policeman's conviction for stealing cocaine from an evidence locker has exploded into a wide investigation of a frame-up, drug dealing and other crimes allegedly covered up by a code of silence in the Los Angeles Police Department.

Ten officers and a police supervisor have been suspended in two internal investigations into corruption within the department.

And federal authorities announced Thursday they would conduct their own investigation into what is believed to be one of the biggest corruption scandals in LAPD history.

"I would not like to label the LAPD as corruption-prone,'' Chief Bernard Parks said Wednesday. "I think we have a small number of officers that have chose to in some instances tarnish their badge''

The police department declined to detail the allegations against the suspended officers, but unidentified sources quoted by the Los Angeles Times said they are suspected of a variety of crimes, from active participation in drug deals to code-of-silence violations that allowed delinquent behavior to go unpunished.

Last week, former Officer Rafael A. Perez pleaded guilty to stealing eight pounds of cocaine from an evidence locker. As part of the plea bargain, he is spilling details and naming names in the process.

Perez reportedly told investigators that he and former partner Nino Durden planted a .22-caliber rifle on the an unarmed illegal immigrant after shooting him in October 1996.

The 22-year-old immigrant, Javier Francisco Ovando, was released from prison on Thursday, three years after he was shot by police officers who authorities believe fabricated evidence used to convict him. It was unclear whether he would face a federal deportation hearing.

"It kind of shakes everything that you believe about in everything,'' Ovando's public defender Tamar Toister said. "The system is not supposed to work like this.''

Another former partner of Perez's, Officer David Mack, was convicted earlier this year of robbing a Bank of America of $722,000 in November 1997 and sentenced Monday to more than 14 years in federal prison.

Prosecutors said Mack went on a spending spree after the bank robbery, including a Las Vegas trip with Perez and another officer.

All of the investigations have targeted the department's Rampart Station, which covers an eight-square-mile area just west of downtown Los Angeles that is home to many recent immigrants from Latin America and Asia.

Residents of the community hung a banner Thursday in support of officers: "The community love the men and women of Rampart Station.''

Tomas Domingo, a 70-year-old Filipino-American, said he was surprised by the reports of corruption. "It still doesn't change my faith in policemen. Some are good and some are rotten.''

"The problem throughout law enforcement is a culture that is closed and self-protective,'' said Terry L. Cooper, a professor and expert on ethics and law enforcement at the University of Southern California.

He believes Los Angeles Police Chief Bernard Parks is trying to change that but says the chief is bucking tradition that has been "sustained and compounded'' for years.