A former Contra Costa County drug task force commander pleaded guilty Wednesday in federal court to five felony counts stemming from a police corruption case that scandalized the Bay Area. 

Norman Wielsch, 51, of Concord, pleaded guilty in U.S. District Court in Oakland to one count of conspiracy to distribute marijuana and methamphetamine, one count of theft from a program receiving federal funds, two counts of conspiracy against civil rights and a robbery count.

He had previously pleaded not guilty to the charges following his August 2011 indictment and changed his plea Wednesday. Six additional charges originally included in the indictment were dropped as a part of a plea deal with the U.S. Attorney's Office. 

Wielsch, the former commander of the now-defunct Contra Costa Narcotics Enforcement Team, Wednesday admitted to committing a series of crimes between 2009 and 2011 that included stealing marijuana and methamphetamine seized during CNET raids and selling the drugs with the help of Antioch private investigator Christopher Butler.

The two previously worked together as Antioch police officers.

The former CNET commander Wednesday told the court that he stole between $30,000 and $70,000 of marijuana and methamphetamine from county evidence lockers and distributed the drugs with Butler.

Wielsch also admitted to teaming up with Butler to target prostitutes and steal cash, cell phones, a computer and other items from them under the guise of making an arrest. He and Butler had scoured Craigslist and other websites in search of their targets and eventually met up with a prostitute and a madame in a San Ramon hotel room in the summer of 2010.

"I don't even believe I did this," Wielsch said before recounting the incident in court Wednesday.

In early 2009, he agreed with Butler to set up a fake sting operation for one of Butler's clients attempting to dissuade her son from selling drugs, Wielsch said.

The pair set up the sting in the CNET parking lot where Wielsch drove up in his police uniform and searched the son's pockets, car and bedroom, where he pocketed thousands of Xanax pills, U.S. Attorney Hartley West told the court.

In court Wednesday, Wielsh said he took full responsibility for his actions.

"That isn't me, but I did it, and I'm sorry," he said.

Wielsch tearfully apologized to his family members and former colleagues, saying he had "tarnished the badge" he wore.

"We did a lot of good before I did those stupid things," he said, referring to CNET.

"I am so sorry to all of the police officers out there who are hard-working, honest people," he said.

Wielsch was taken into custody after Wednesday's hearing, and faces a minimum of 10 years in prison and at least $150,000 in fines when he is sentenced on Feb. 19.

A co-conspirator of Wielsch and Butler's, former San Ramon police officer and former CNET second-in-command Louis Lombardi, pleaded guilty earlier this year to selling drugs given to him by Wielsch. He also admitted to other crimes, including stealing drugs and $40,000 during CNET searches and seizures.

Stephen Tanabe, 48, a former Danville police officer, was awaiting trial on charges that he conspired with Butler to set up the spouses of Butler's clients for DUI arrests.

Outside of the courtroom Wednesday, Wielsch's attorney, Michael Cardoza, said his client was the only one of the four defendants who admitted to his crimes the day of his arrest.

The attorney said he did not have an explanation for Wielsch's criminal behavior after more than 20 years in law enforcement.

"Norm Wielsch did serve the public in an honorable way for quite a number of years, and then he did go bad," he said.