Informers: A 'necessary evil' in city's drug war? A probe is revealing risks of polices heavy reliance on CIs.

The Philadelphia Police Department is heavily dependent upon informants to build cases against drug dealers, a reliance whose risks are painfully apparent as a probe expands into the conduct of its undercover narcotics unit.

Officer Jeffrey Cujdik, whose soured relationship with a confidential informant triggered a federal-local investigation into the Narcotics Field Unit, employed informants to justify 95 percent of his drug searches in the last three years, records show.

An Inquirer analysis of 186 search warrants that Cujdik was granted since 2006 shows that the officer cited confidential informants in nearly all his cases. None listed an undercover drug buy that he personally made, and only one listed a buy by another officer.

Rather, confidential informants - often drug dealers themselves who work for cash or leniency - did most of the transactions.

Philadelphia's practices are similar to those of other big-city forces, according to several studies.

Deputy Police Commissioner William C. Blackburn, who oversees the Narcotics Unit as the head of major operations, said there was a reason for the Philadelphia antidrug force's "heavy reliance" on informants.

"Informants give us an opportunity to get into an area where an undercover police officer wouldn't be able to go," he said in an interview last month.

Cujdik's relationship with one informant has shown the weakness of the system.

Investigators began to pursue Cujdik (pronounced CHUH-dik) last year after his most productive informant, Ventura Martinez, alleged that the officer had repeatedly fabricated evidence to obtain warrants. In January, Cujdik was put on desk duty and ordered to turn in his service weapon.

According to sources, FBI and Internal Affairs investigators are now looking at Cujdik's work with at least four informants, and suspicion has spread to other members of his squad. Philadelphia's public defender has sought to overturn 53 convictions allegedly based on tainted searches.

According to Cujdik's affidavits, the officer cited Martinez - code-named "Confidential Informant 103" - in 43 percent of his 186 search warrants in the last three years. Martinez provided tips to Cujdik and made controlled drug buys from the dealers he informed on. But Cujdik also trusted Martinez sufficiently that he asked him to make drug buys from dealers he had never met.