The Los Angeles Police Department and district attorney's office are covering up widespread and illegal wiretapping, the Los Angeles public defender's office charged Wednesday, in the latest round of a growing legal battle that's piqued the interest of electronic privacy advocates. John Gilmore, co-founder of the Electronic Frontier Foundation, said the case shows why citizens need communications that are protected by encryption. "We have the metropolitan police department of one of the largest cities in America doing illegal wiretaps, and covering it up by falsifying the statistics," he said. Last year, the LAPD and prosecutors admitted to concealing the role that court-authorized wiretaps played in 58 criminal cases since 1993 -- a practice that defense attorneys say violates federal and state laws and cheats defendants of the right to challenge the legality of a wiretap. In November, Superior Court Judge Larry Fidler ordered prosecutors to end the practice, and to inform defendants who had been subject to secret wiretaps in the past. Deputy Public Defender Kathy Quant charged Wednesday that prosecutors violated that court order. "They're lying," Quant told Fidler, "and I can prove that." Quant claimed that her office's investigation has uncovered as many as 425 cases that may be tainted by secret wiretapping, and which the district attorney's office has yet to acknowledge. Some of the wiretaps, she alleged, were done without a court order. Los Angeles Deputy District Attorney Robert Schirn admitted to missing some cases in which wiretaps were used, but insisted that the office substantially complied with the court order. "It's an impossible burden, I think, to identify every case. We've done our best," Schirn told the court. Schirn also dismissed the public defender's allegations as speculation. "Some of these cases clearly don't involve wiretaps," he said. Particularly troubling to electronic privacy advocates is the charge that prosecutors manipulated public wiretap statistics by using a single court order to obtain multiple taps. One order, targeting a cellular telephone company, lasted two years and tapped 250 phones, but was reported to state and federal authorities as a single surveillance. "This case shows that ordinary people need communications that are protected by encryption so they won't become victims of this official but illegal type of wiretapping," said EFF's Gilmore. David Banisar, a Senior Fellow with the Electronic Privacy Information Center, consulted for the Los Angeles public defender's office on the case earlier this year. He accuses police investigators of ignoring so-called minimization requirements -- the legal requirement that innocent parties be spared from surveillance. "They pretty much sucked everything down," said Banisar in an interview early this month. "There were some cases where they tapped pay phones and recorded literally hundreds of thousands of innocent people." "This case provides a good reason to reverse CALEA," says Gilmore, referring to the 1994 Communication Assistance for Law Enforcement Act that requires phone companies to make wiretapping easier for all law enforcement agencies. "If you build an infrastructure that encourages wiretapping, it will be abused. The only question is, how many years or decades will it take to find out its been abused." Fidler set a date of 3 November for testimony and evidence on the matter. They can see you... Read about how and why in Surveillance , a ZDNet News Special. Take me to the Hackers news special