One woman covered her ears with her hands and another bolted from the courtroom as a witness described how Mooney was gunned down in the Pine Watson Shopping Center in Langhorne while waiting for his fiancee to get a prescription filled.
His fiancee was Starlet Derby, Colson Derby's ex-wife.
Colson Derby, 40, of Levittown, is charged with criminal homicide and weapons offenses in the slaying of Mooney, 37, who had been living with Starlet Derby in Langhorne. He was ordered held for trial, and arraignment was set for Sept. 23 in Bucks County Court in Doylestown.
Derby pleaded not guilty. He is being held without bail in Bucks County Prison.
One witness, Ronald Koreck, testified that he saw the shooting from inside a pizza shop. He said Derby rolled up to Mooney's car and fired a pistol from about three feet away. The men never spoke, said Koreck, who added that Derby rolled his wheelchair away quickly afterward.
Police arrested Derby in his car about 15 minutes later on Interstate 95 near the Street Road exit. They said he had two handguns in his waistband - a .38-caliber revolver and a 9mm semiautomatic, which they say was the murder weapon.
State Trooper Donald Thomas testified that Mooney was shot five times with 9mm bullets.
The defense called no witnesses.
After the hearing, county prosecutor Terence P. Houck said: "This isn't a who-done-it, that's for sure."
The motive remains a mystery.
Friends of Derby, some of whom arrived at the hearing in a car with "Free Colson" painted on the back window, maintain that Derby may have been driven to violence because, they say, Mooney had raped Derby's 16-year-old daughter.
The girl filed a complaint May 30 with Middletown police, alleging that such a rape took place several months earlier, according to police.
According to Houck, the matter was under investigation at the time of Mooney's death. In fact, Mooney was to have been interviewed by police on the day he died.
Starlet Derby contends that there was no rape and that her ex-husband was motivated by jealousy.