Prosecutors on Monday accused six Philadelphia narcotics officers on trial in a wide-ranging federal corruption case of "disrespecting their badge" by shaking down suspects, stealing hundreds of thousands of dollars, and lying about it on their police reports.

But that mild disparagement paled next to the invective defense lawyers unleashed in their opening statements to refer to their clients' accusers.

"Trashy," "disreputable," "greedy," "sociopathic," and even "odoriferous" were deployed to describe the government's 19 primary witnesses, many of them admitted drug dealers, who are expected to testify that they were targeted by the group.

"If you have 19 bags of trash," defense attorney Jack McMahon told jurors, "you don't have better trash. You just have a pile of trash."

With that exercise in insult, the racketeering conspiracy trial began Monday for Officers Thomas Liciardello, Brian Reynolds, Michael Spicer, Perry Betts, Linwood Norman, and John Speiser, former members of the Philadelphia Police Department's elite Narcotics Field Unit accused in what Police Commissioner Charles H. Ramsey has called "one of the worst cases of police corruption I have ever seen."

It also laid bare what will likely become the central question for the jury of six men and six women weighing the officers' fate: Whose testimony is more credible - a group of cops accused in kidnappings, extortions, brutal assaults, and drug dealing, or admitted criminals who say their pasts are no excuse for police to break the law?

Prosecutors allege that from 2006 to 2012, the officers, led by Liciardello, ran roughshod over the rights of drug suspects, stealing more than $400,000 in cash, drugs, and personal property while using extreme force and falsifying police records.

Targets who resisted, they said Monday, were dangled over balconies, threatened with the seizure of their homes, or held in dank hotel rooms for days.

Already, the allegations have prompted dozens of civil rights lawsuits against the officers and led local courts to toss about 450 of their former drug cases.

"Make no mistake about it," Assistant U.S. Attorney Anthony Wzorek told jurors. "Taking money while armed and using your authority as a Philadelphia police officer is robbery even if it's illegal drug money."

Wzorek offered jurors a preview of testimony to come, including that of Rodolfo Blanco, a Northeast Philadelphia heroin dealer who accused Liciardello and others of stealing $12,000 from him in 2006 and holding him in an airport hotel room for days while they threatened his family.

Victor Rosario, Wzorek said, will testify that Liciardello and Reynolds took nearly $12,000 from him in 2010 as well as an iPod, jewelry, and a Rolex watch they found during a search of his house. Rosario later told agents when he ran into Reynolds in court, he was wearing the stolen watch.

The defense was quick to offer alternate versions Monday of each incident.

The Rolex Rosario spotted on Reynolds wrist had been purchased years before the man's arrest, said McMahon, Reynolds lawyer, adding that he has the paperwork to prove it.

Defense lawyers said Blanco agreed to cooperate with Liciardello's crew to set up drug dealers higher up the chain. They housed him, with the approval of the District Attorney's Office, in the hotel to protect him while he worked with investigators, McMahon said.

"They all went out and played pool and had beers together one night," he said. "Mr. Blanco was there voluntarily."

Overall, McMahon said, the FBI's eight-year investigation of the officers was plagued by similar sloppiness. He accused agents of failing to interview key witnesses including the officers' supervisors, who were present at many of the incidents that now make up the government's case.

Defense lawyers said Monday that they planned to call many of the department's top brass to testify on behalf of their clients. Many of the indicted officers are also expected to take the stand.

But the defense reserved its harshest words Monday for the star witness of the government's case: Jeffrey Walker, a 24-year police veteran and former member of the drug squad who agreed to testify against the others after being arrested in a 2013 sting operation.

FBI agents caught him planting nearly 28 grams of cocaine in the car of a South Philadelphia drug dealers and later stealing $15,000 and five pounds of marijuana from the man's house.

Records of Walker's interviews with the FBI, mentioned in court Monday, suggest he began giving up his colleagues almost from the moment of his arrest, and he has not stopped talking since.

At various points, he has implicated lawyers, more than a dozen fellow officers, and even two barmaids at the unit's favorite watering hole, the Post Office Café in Bridesburg, in illegal activity.

Defense lawyers variously described Walker on Monday as a "despicable, rotten liar and thief," a "narcissistic amoral creep" and a man "suffocating in his own quicksand of disgusting corruption."

"Not only is he a drinker, he's a drooler," said Spicer's lawyer, James Binns, of Walker's purported habit of passing out at bars.

Later, Binns' colleague, Jeffrey Miller, who is representing Liciardello, apologized for the day full of name calling. But he promised there would be much more.

"We've got the sticks and stones," he told jurors, "and you're going to see them."

Opening statements in the case are expected to resume Tuesday. The trial is scheduled to last 10 weeks.