A confidential police informant's disavowal of more than 50 narcotics cases has drawn in other undercover officers who worked closely with Officer Jeffrey Cujdik in the last six years.

Philadelphia's public defender filed challenges to overturn 53 convictions after informant Ventura Martinez alleged that Cujdik fabricated evidence in the cases. An Inquirer analysis of the court files identified about a dozen undercover officers who played critical roles in building the cases.

Assistant Public Defender Bradley S. Bridge filed the legal challenges this month after interviewing the paid informant, whose seven-year partnership with Cujdik went sour last year. Martinez's allegations have triggered a federal-local task-force investigation into the Philadelphia Police Department's Narcotics Field Unit.

A review of the court files in 48 of the challenged cases shows that Martinez often worked closely with other officers in Cujdik's squad. In several cases Martinez has renounced, officers other than Cujdik supervised the informant while he made the purported drug buys that gave them the probable cause to obtain search warrants.

According to court files, seven officers other than Cujdik signed affidavits that persuaded judges to grant search warrants that led to 13 of the challenged convictions. Before submitting affidavits, officers swear that the information in them is true.

In most of the challenged cases, at least one officer conducted surveillance during the purported undercover transactions that Martinez has now called into question. In alleged transactions that contributed to 15 convictions, police said that Martinez handed over the drugs he bought to officers other than Cujdik.

In 27 cases, 12 officers other than Cujdik are listed as the arresting officers. The arresting officers are usually, though not always, involved in developing the evidence in narcotics cases.

Martinez was a highly productive informant who not only initiated investigations with original tips but also was frequently called on short notice to make drug buys from dealers targeted by investigators. Cujdik boasted in court papers that Martinez - known as Confidential Informant 103 - was responsible for about 200 arrests. The cases he has renounced account for only part of his work.

Bridge said he interviewed Martinez about more than 100 cases that the informant alleges were tainted. The defender said the 53 cases he is challenging represent those that resulted in convictions of defendants whom he was able to contact.

The defender's challenges name only Cujdik. And they offer no specifics about the fabrications that Martinez alleges occurred.

But if Martinez's claims are credible, the implication from reading the original filings is that Martinez and Cujdik could not have acted alone all the time.

"This raises important questions about the entire process of utilizing confidential informants and demonstrates yet again the critical role the courts have in acting as a check on such abuses," Bridge said in a statement last week after filing the challenges.

Cujdik's lawyer, George Bochetto, has called Martinez a career criminal and a liar who incriminated Cujdik out of anger. The Fraternal Order of Police has denounced Martinez, but the breadth of his allegations has put the police union in the uncomfortable position of repudiating an informant whose work helped Cujdik and other officers win commendations.

Efforts to talk to the officers whose names appear in the impugned cases were unsuccessful. The police union has advised officers not to comment. The Inquirer left John McNesby, president of FOP Lodge 5, a telephone message and a detailed e-mail seeking a response. Lt. Frank Vanore, a police spokesman, said the department would not comment on the case. A police employee who answered the phone at the Narcotics Bureau on Friday said four of the officers were not available.

"I'd love to help you, but the FOP advised us not to talk about it," said Lt. Joseph Bologna, who supervised Cujdik until 2007. According to court records, Bologna had direct contact with Martinez in many of the cases the informant has renounced.

District Attorney Lynne M. Abraham has declined to comment on the challenged cases until the FBI and police Internal Affairs investigators conclude their investigation. Prosecutors have sought delays in pending court cases until the inquiry is completed.

Police Commissioner Charles H. Ramsey has promised to take action once the task force has finished its investigation.

Cujdik's productive seven-year relationship with Martinez, 47, came unhinged in October when Martinez's identity was disclosed in court by a defense lawyer. A private investigator discovered that Cujdik rented a house to Martinez's girlfriend, in apparent violation of department regulations that prohibit personal relationships with informants.

While Internal Affairs investigators looked into Cujdik, Martinez grew impatient with authorities and took his allegations to reporters.

Martinez's initial allegations were first reported in the Philadelphia Daily News. Since then, the inquiry has moved along two distinct paths as investigators broadened their examination to also look into allegations that the narcotics officers abused small-shop owners while executing search warrants for drug paraphernalia.

The more serious allegations concern Martinez's charges that Cujdik fabricated evidence in some cases to obtain search warrants. Sources say investigators are now looking into Cujdik's relationship with three confidential informants in addition to Martinez.

Cujdik, 34, a 12-year veteran, has surrendered his service weapon and was assigned to desk duty in January.

Two other officers were recently removed from street duty because of the investigation, though they still have their sidearms and have not been relieved of authority.

Cujdik's partner, Robert McDonnell, who had frequent contact with Cujdik's informant, has been assigned to a desk job in the Narcotics Bureau. Jeffrey Cujdik's brother, Richard, whose name did not appear in any of the 53 cases being challenged in court, has been assigned to the 15th District, according to Chief Inspector Anthony DiLacqua, head of the department's Office of Professional Responsibility.

The public defender's action expands the sphere of known cases that Martinez has renounced. The Daily News reported that the informant said Cujdik began fabricating evidence in 2005, but the defender is challenging cases that were initiated as early as 2003.

Not all of Martinez's undercover activity was allegedly manufactured. His identity was exposed by Raul Nieves, a dealer who acknowledged that he sold marijuana to the informant once but said he turned away the aggressive Martinez when he tried to buy a second time. The dealer was outraged that Cujdik had apparently fabricated a second buy in order to amass evidence to get a search warrant. Nieves was convicted.

Martinez declined in a brief telephone interview to explain the details of the cases that he has renounced. He said he had stopped giving interviews on the advice of federal investigators.

Thirteen of the convictions Martinez renounced were based on sworn affidavits signed by seven officers: McDonnell, Mario Cruz, Richard Eberhart, Charles J. Scollon IV, Gregory P. Kovacs, Stacey M. Wallace, and Thomas J. Tolstoy.

In one of the earliest cases that Bridge has challenged, Cujdik signed an affidavit crediting Martinez with making two narcotics purchases in 2003 from Ada Anaya at 2833 N. Waterloo St. Both buys were managed by other officers.

In one purchase, Sgt. Bologna supplied Martinez with $20 that he used to buy a green-tinted packet of cocaine, according to the affidavit. Cujdik said Bologna recovered the drugs from the informant. Martinez made another purchase eight days later with another officer, according to the affidavit.

The defender's challenge does not specify which part of the Anaya case was allegedly fabricated. Anaya, who was then 37, was arrested May 1, 2003, and pleaded guilty to drug charges in 2004. She was sentenced to one to two years in prison.

In several cases that Martinez now says were fabricated, Cujdik appears to have played little, if any, role.

A Dec. 3, 2003, raid of a rowhouse in the 2600 block of North Darien Street was based on two controlled buys that Martinez allegedly conducted under the supervision of three other officers, according to Wallace, the officer who signed the affidavit. The raid resulted in the conviction of three people, who got jail terms.

Contact staff writer Andrew Maykuth

at 215-854-2947 or amaykuth@phillynews.com.

Inquirer staff writer Barbara Boyer contributed to this article.