A Concord private eye at the center of a Contra Costa County law enforcement scandal admitted that he hired female decoys to drink with men he was targeting in stings that led to their drunken-driving arrests, according to a transcript of his interview with detectives.

"It all centered around the introduction of the decoy to the subject," Christopher Butler said, according to a partial transcript of the March 17 interview obtained by The Chronicle. "It had to be what I referred to as seamless. ... And it shows that, yeah, I was very careful in how these things went down. No one just plowed into a bar, called the guy and said, 'Hey, meet me at this bar and let's go drinking.' "

Butler, 49, a former Antioch police officer, made the statements during a nine-hour interrogation with detectives from the Contra Costa County district attorney's office and state Department of Justice.

He also told the detectives that clients had been referred to him by a San Ramon attorney who represented women in divorce cases - women who wanted videotaped evidence that their husbands were cheating.

In one instance, a disgruntled wife paid him $2,500 to "obtain irrefutable proof" that her husband "was actively seeking other women," Butler said in a statement he gave to investigators.

Husband given transcript

Hal Jewett, Contra Costa's senior deputy district attorney, provided the statement and interrogation transcript to the woman's former husband last month and told him in a cover letter that he considered the man's drunken-driving arrest "one of the most deplorable legal practices I have ever heard of."

Butler's attorney, William Gagen, said the transcript and the private eye's one-page written statement that outlined the man's 2008 sting was not an admission of guilt.

"It was not criminal conduct," Gagen said. "Now, is it an unseemly kind of investigation process? I think the answer is 'yes.' And I think Mr. Butler is aware of that now."

Authorities arrested Butler on Feb. 16 as part of an investigation into Norman Wielsch, a former commander of a state anti-narcotics unit who allegedly stole confiscated drugs from evidence lockers and passed them on to Butler, a close friend.

Connections probed

As the investigation has progressed, Butler's tactics and his connections to Bay Area law enforcement officers have also come under scrutiny.

On April 21, Butler pleaded not guilty to charges that he bribed a Contra Costa deputy sheriff, Stephen Tanabe, 47, to arrange the November drunken-driving arrest of a man outside a Danville bar.

Tanabe, a friend of Butler's, denied the bribe allegations and also pleaded not guilty to felony charges that he had conspired to falsely arrest two additional men at Butler's request.

In all, prosecutors suspect Butler orchestrated stings that led to the arrests of at least five Bay Area men.

A reserve sheriff's deputy told investigators that Tanabe nicknamed the practice a "dirty DUI" - an arranged arrest designed to give the target a criminal record as he was embroiled in divorce or child-custody proceedings.

Butler told investigators that women hired him to obtain evidence of their husbands' infidelity. He said he produced that evidence by enlisting decoys to approach the men through online dating sites and seemingly random public encounters.

Although he directed the decoys to drink with the men at bars, Butler said he had never promised clients that the night would end with a DUI arrest.

"As I would tell all my clients ... if he's in the bar and he drinks, he's going to drink, I said, I will always say that there's no guarantee he's going to drive," Butler told detectives. "You know, he can call a cab, he can call a friend."

A 'successful sting'

According to Butler's written statement, one "successful sting resulting in a DUI" was set in motion Dec. 3, 2008, when Susan Dutcher, a Brentwood elementary school teacher, walked into his Concord office and paid him a $2,500 retainer. Butler said Dutcher was the second referral he had received from Mary Nolan, a San Ramon divorce attorney.

In the first referral, Butler said he was "contracted" by Nolan to conduct a July 2007 sting on Declan Woods, 46, a contractor in Clayton who was in the midst of divorcing one of Nolan's clients.

Butler said he had been paid $1,500 - although he did not make it clear if he was paid by Nolan or Woods' ex-wife - to hire two female decoys to approach Woods and drink with him at his local bar. Butler told investigators he paid the female decoys $25 an hour with a four-hour minimum for their work.

After the decoys suggested Woods follow them home to Walnut Creek for more partying, Butler called Clayton police dispatch and gave a description of Woods' truck, which resulted in Woods' DUI arrest.

Butler said he had videotaped Woods being handcuffed and put into a squad car, and that Nolan was "thrilled" with the visual evidence.

Nolan did not respond to e-mail and phone messages.

The setup

The sting of Susan Dutcher's estranged husband, David Dutcher, proceeded in much the same fashion, Butler told detectives.

He said he had hired a blond decoy to contact the Lockheed Martin engineer through match.com. The woman made a date to meet Dutcher, then 46, at the Old Spaghetti Factory in downtown Concord and invited a second blond decoy to join them, Butler said.

"I didn't know if he was going to be attracted" to the first decoy, Butler said. "Maybe he wouldn't be attracted to them at all. I had no idea."

Butler told investigators he had sat at a nearby table and recorded the three drinking alcohol, which the first decoy paid for.

As the 10 p.m. closing time neared, Butler said, one of his decoys alerted him that Dutcher wanted to drink at another bar. Butler said he had called a friend on the Concord police force, Officer Don Lawson. According to Butler's website, Lawson worked as his investigation firm's identity theft expert, and the two men grew up together.

"I said, 'We got a case here where, you know, this guy, we're watching him at the bar and I think he's over the limit. ... Where are you?' " Butler told investigators.

Lawson replied that he was about to go off-duty, but agreed not to after Butler told him, " 'Wait five, 10 minutes for me, please, because I think this guy is going to drive,' " Butler told the detectives.

The arrest

Lawson arrested Dutcher less than 2 miles away for DUI as Dutcher followed the convertible carrying the two blond decoys.

In his police report on the arrest, Lawson did not say Butler or anyone else had alerted him to a drunken driver on the road. Instead, Lawson wrote that he had seen Dutcher's truck at a stoplight on Clayton Road, then pulled it over after the driver broke the speed limit.

Investigators asked Butler whether he had paid Lawson, Concord's two-time Officer of the Year, to make the arrest.

"No, (Lawson) was not compensated," Butler replied. "I swear to God. I'll get on a polygraph. He was not compensated for that."

Lawson, who retired in 2009, did not respond to phone and e-mail messages seeking comment.

Back to court

David Dutcher said he plans to submit the interview transcript and Butler's statement to a divorce court judge as proof that he unfairly lost custody of his three children because of his drunken-driving conviction. His former wife did not respond to requests for an interview.

Dutcher said he had always held suspicions about the events that led to his arrest, but that reading Butler's statements had made him sick.

"You learn your wife paid for this kind of stuff and that her attorney was in on it?" Dutcher said. "And I lost my kids over it? Guess they were all laughing at me for a long time. ... Wonder how they feel now."