NEW YORK - An anonymous tip about a crooked cop grew during the past three years into a sweeping internal corruption probe on the under-the-table practice of fixing tickets, with dozens of wiretaps, 10,000 intercepted calls and an officer undercover as a barber in a sting, authorities said.

Thirteen New York Police Department officers, two sergeants and a lieutenant were slapped with criminal charges Friday, just three days after the embarrassing arrests of five officers in a separate gun-running probe.

Police Commissioner Raymond Kelly said it was "difficult" to have to announce for the second time in a week that his officers had been arrested for misconduct.

"These misdeeds tarnish the good name and reputation of the vast majority of police officers who perform their duties honestly," he said.

Kelly said the probe included 300 cases that are being handled internally. Bronx District Attorney Robert Johnson said he hoped the criminal charges send a message that corruption would not be tolerated. The city lost about $2 million in killed-off tickets, he said.

The majority of the arrested are officials with the Patrolmen's Benevolent Association, arguably the most powerful law enforcement union in the nation, with 23,000 members. Union leaders say the practice of making a ticket disappear for a friend or family member was not only sanctioned, it was condoned at the highest levels of the nation's biggest police department.

Union President Patrick Lynch vowed that when the dust settled, they'd prove it.

"Taking care of your family, taking care of your friends is not a crime," he said. "To take a courtesy and turn it into a crime is wrong."

Hundreds of union members went to support the officers, some in suits, others dressed in jeans and sweat shirts, clogging the street near the Bronx courthouse, filling the hallways and applauding in court after the officers left. Detective Steven McDonald, a city hero paralyzed decades ago, was in the courtroom in a wheelchair, with an American flag on this lap.

The officers pleaded not guilty to hundreds of charges including misconduct, grand larceny, records tampering and obstructing governmental administration. Among those charged was Jennara Cobb, an internal affairs bureau lieutenant who pleaded not guilty to charges she leaked information to union officials about the probe.

As a result of her meeting, word quickly spread and union delegates started to alter the way they fixed tickets, prosecutor Jonathan Ortiz said.

"The investigation was significantly compromised because of her actions," he said.

Her attorney, Philip Karasyk, said she had been unfairly singled out.

"That wiretap was leaking like a sieve," he said.

The case started with an anonymous tip in 2009 that a 40th Precinct officer, Jose Ramos, was selling drugs in his barbershop. An undercover officer hired as a barber monitored Ramos, who also was accused of shuttling drugs while in his police uniform.

"He sold his shield, he violated his oath," Assistant District Attorney Omer Wiceyk said.

Ramos was recorded saying he "stopped caring about the law a long time ago," the prosecutor said.

Ramos pleaded not guilty to drug and other charges. His attorney, John Sandleitner, said the charges were ridiculous.

"The DA's office basically made a circus of this," he said.

While officers were listening to Ramos on a wiretap, they caught calls from people seeing if Ramos could fix tickets for them, prosecutors said. The conversations led to more wiretaps that produced evidence of additional officers across the borough having similar conversations, they said.

There are generally three ways the citations are fixed: They are voided by a ranking official, a copy is ripped up before it reaches court or the officer doesn't appear on the day of the summons.

Kelly said the case exposed departmental weaknesses that were swiftly addressed. The NYPD installed a new computer system that tracks tickets and makes it much more difficult to tamper with the paper trail. Kelly also created a new unit to sit in on traffic court testimony and comb through paperwork to ensure none of the methods is being wrongly employed.

He said the practice was wrong and can't be glossed over as "courtesies" or as part of an acceptable culture.

"Members of the public don't accept favoritism," he said. "They resent it, as well they should."

Earlier this week, federal prosecutors in Manhattan brought conspiracy and other charges against five current and three former officers, alleging they were part of a gun-running ring. In two other recent unrelated federal cases, one officer was charged with arresting a black man without cause and using a racial slur to describe the suspect and another was charged with using a law enforcement database to try to trump up charges against an innocent man.

Longtime police historian Thomas Reppetto said it's "not the best time for the department."

"Does it rise to the level of the great scandals that have occurred in the past? No," he said. "Ticket fixing is not on the same level as drug dealing."

Kelly said the cases could undermine morale, "But I look at the work done every day and it's outstanding."

The highest-ranking union members charged in the probe were Joseph Anthony, Michael Hernandez and Brian McGuckin.

The other officers were union representatives, and all were stationed in Bronx precincts: Virgilio Bencosme, Luis R. Rodriguez, Jaime Payan, Eugene P. O'Reilly, Christopher Manzi and Jason Cenizal.

Ramos' supervisor, sergeant Jacob G. Solorzano, also was charged.

The officers pleaded not guilty and were released.

While on the wiretap, investigators also uncovered that three other officers and a sergeant covered up an assault for a friend, prosecutors said. Sergeant Marc Manara and Officers Ruben Peralta, Jeffrey Regan and Christopher Scott, all from the same precinct, were arrested as well. The friend was arrested on the initial assault charge, prosecutors said. The officers pleaded not guilty.

In addition, three others were charged along with Ramos with insurance fraud and other crimes.

The last serious corruption scandal for the NYPD was the so-called Dirty 30 case from the early 1990s. More than 33 officers from Harlem's 30th Precinct were implicated in the probe, with most pleading guilty to charges including stealing cash from drug dealers, taking bribes, beating suspects and lying under oath to cover their tracks.