As the trial of a Washington Township police officer who arrested an assemblyman on suspicion of drunken driving opened Wednesday, attention was focused on the events of July 31, 2012.

That's when Officer Joseph DiBuonaventura pulled over Assemblyman Paul D. Moriarty (D., Gloucester), initiating a high-profile controversy with political undertones.

DiBuonaventura faces 14 charges - including official misconduct and tampering with records - relating to the arrest, which began when he stopped Moriarty's blue Nissan Murano (with identifiable legislative license plates) in the parking lot of a Chick-fil-A restaurant, saying Moriarty had cut him off. The officer has since been suspended without pay.

Some facts are not in dispute. Moriarty, a former township mayor, had just left a Nissan dealership and was traveling north on the Black Horse Pike in Turnersville. The officer claimed he smelled alcohol, and Moriarty was ordered to do field sobriety tests before DiBuonaventura handcuffed him and took him to the police station for a breath test.

Moriarty refused the test. "I had no faith in the process at that point," he said in court Wednesday. He was charged with DWI, refusal to submit to the test, and failure to maintain a lane. But evidence - including video footage from the officer's police cruiser - refuted DiBuonaventura's narrative and the criminal charges against Moriarty were dismissed.

Prosecutor Audrey Curwin, referring to DiBuonaventura's police report, told jurors, "None of this happened."

But the allegations against Moriarty remained a focal point in the courtroom as he testified.

Moriarty said he felt "targeted" by DiBuonaventura, though no one could explain why.

"I don't know why he did it," Moriarty told defense attorney Louis Barbone during cross-examination. "It's a mystery to me."

Curwin said in her opening that DiBuonaventura had been given unsubstantiated information that Moriarty was at the dealership and possibly drunk, and decided it was "his way to get Paul Moriarty."

Barbone offered a different take: An employee at the dealership called his cousin, a detective in the Police Department, saying Moriarty was acting belligerently and was possibly intoxicated. Another detective at police headquarters, who overheard the conversation, relayed that information to DiBuonaventura. Barbone called that a "credible" tip, saying DiBuonaventura acted "instinctually."

Moriarty testified that on the day of the arrest, he had a conversation with a dealership employee about his displeasure with the auto mall because it had supported another Assembly candidate's nomination. But he said he remained calm as he considered whether to buy his leased car or lease another. He maintains he had nothing to drink.

Barbone pressed Moriarty as to why he refused the breath test even though he had voted for legislation dealing with such requirements. Moriarty reiterated a previous explanation, saying he couldn't trust the process and the arrest was unwarranted: "Even in the military, you don't have to follow an illegal order."

Moriarty also said he wanted to consult his attorney, although that is not part of the process under state law. "If I had to do it again," he said, "I certainly would" take the test.

Jurors heard much about Moriarty's day, which ended with his having blood drawn at Cooper University Hospital in Camden.

Administered about 11:30 p.m., several hours after his release, the test was negative for alcohol.

Moriarty grew visibly upset while testifying, bowing his head as he recalled a "media assault" that began the day of the arrest. "All you have is your reputation," Moriarty said, "your integrity."

Last year, legislation Moriarty sponsored requiring new police vehicles to be equipped with recording devices was signed into law.

The trial continues Thursday.