Farm foreman Roberto Ayala was making his rounds on the vast Moore Brothers Farm in Colusa County that July afternoon when he stopped to turn on an irrigation pump.
He opened the power-control box, and a pipe bomb planted inside exploded. The blast electrocuted the 43-year-old foreman, blowing off his left arm and setting him on fire in front of his 7-year-old son, who ran nearly two miles to get help, to tell somebody, he would testify later, "that my dad died."
Nearly five months after the killing on July 16, 2011, authorities arrested a third-generation scion of the Colusa County farming dynasty that employed Ayala.
Now, 48-year-old Paul Moore is on trial for murder in a case that has spotlighted a succession fight in a lucrative 1,800-acre farming operation that produces rice, wheat, walnuts, alfalfa and other crops, with natural gas on the side.
"They're worth millions," Colusa County District Attorney John Poyner said of the farming operation. "I mean millions."
Graying and pale, Moore, the son and nephew of the two aging brothers who own the farm, sat at the defense table during testimony last week looking almost uninterested. He appeared to nod off at one point while his father, Roger, testified about his son's efforts to reintegrate himself into the family business.
The theory laid out by prosecutors holds that Paul Moore did not like Ayala, who had been working on the farm for 19 years, and may have been jealous of him. Roger Moore made Ayala the foreman even as his son, who suffered a back injury while working in the construction business, returned to the farm looking for work.
With Roger Moore now 72 and his brother Arlan "Gus" Moore, 76, suffering from dementia, Paul feared that the daily operation of the family business would fall under the control of an outsider, according to Poyner.
"Somebody has to be in charge," Poyner said in an interview. "Roberto clearly in the pecking order was above Paul. Paul didn't like that at all."
Defense attorney Linda Parisi agrees that succession to the leadership at Moore Brothers played a critical role in Ayala's death. But instead of Paul Moore, Parisi implied in her cross-examination of witnesses and flatly charged in an interview outside the courtroom that Paul's 50-year-old cousin, Peter, is the more likely suspect.
Parisi pointed to angry phone messages that Peter left with his Uncle Roger and to text messages in which he suggested he would harm Roberto Ayala.
"After his back injury, Paul was back working on the farm with his family and making a lot of contributions," Parisi said. "While he may have from time to time had professional differences with Roberto, he never made any physical threats. The only threats against Roberto have come from Peter."
The family farm was established by Richard and Mimi Moore, who decades ago moved to Colusa County and started buying agricultural property around the little town of Grimes, about 65 miles upriver from Sacramento. The couple left the farm to their sons, who maintained the family legacy which is now thrown into doubt by the murder trial.
Poyner said that in the days after the fatal explosion, investigators focused their suspicions on Peter Moore, a self-employed landscaper.
Peter had complained about his belief incorrectly held, according to Poyner and family members that his father, Gus, had cut him out of his will, investigators said.
In an angry message he left on his Uncle Roger's phone, Peter said he wanted to "get a chance to plow my grandfather's ground." He also accused Ayala of assorted improprieties, and Roger Moore testified that he heard secondhand that his nephew had threatened to kill him.
"We were all over Peter," Poyner said. But even with the assistance of the FBI and other federal agencies, "we couldn't find a thing on him," the DA said.
In the meantime, Colusa County detectives received two letters in the mail in which the writer claimed responsibility for the Ayala killing. One said, "I am military trained and an expert in Vietnam devices." The letter called the blast "an MS-13 job," in reference to the Los Angeles-based Salvadoran street gang Mara Salvatrucha. It said Ayala was killed "for some deal gone wrong."
The second letter contained what investigators said was an accurate diagram of the bomb that killed Ayala.
Interviews with additional Moore family members turned the detectives' attention toward Paul. According to a search warrant affidavit, investigators learned Paul in the past had experimented with fashioning explosive devices. Prosecutors also became aware that he had been convicted of tapping his ex-wife's phone. Authorities said the eavesdropping expertise demonstrated a knowledge of electrical circuits that could have been applied to planting a bomb in a power box.
Another of Paul Moore's cousins, Dave Moore who also is the stepfather of Paul's ex-wife testified last week that Paul had said he wanted to run the farm.
"He declared that once he starts taking over the ranch, he would fire those Mexicans," Dave Moore testified, referring to Roberto Ayala and his brother, Eduardo, who also works on the farm. Dave Moore's wife testified she was present when Paul made the remark and that it came about a year and a half before the bombing.
On the day of his arrest, Dec. 6, 2011, detectives searched Paul's home and found a piece of paper with indentations that matched up to the bomb diagram that had been mailed to investigators. The search also recovered a label-maker that, according to testimony by technical experts, was identical to the device used to make the labels applied to the envelopes mailed to Colusa County sheriff's investigators.
In testimony Thursday, Paul's father sought to walk a line between loyalty to a slain foreman he very much liked and a defendant son he had tried to involve in the family business. Roger Moore downplayed animosity that may have existed between the two, saying, "I don't think it would be accurate" to say that Ayala ordered Paul Moore around. He said he thought Paul seemed to be trying to assist the foreman.
Even though Ayala was his "head man," Roger said, he was going to cut his son in as a 50 percent partner. He said that when Paul returned to the farm, "I wanted him to work with the employees and respect them, and to have them respect him back."
In response to questions from Parisi, Roger Moore deflected attention back on his nephew, saying that in their conversations, Peter "had been critical of the Ayala family."
Peter Moore is scheduled to take the stand when the trial resumes today.
Call The Bee's Andy Furillo, (916) 321-1141. Follow him on Twitter @andyfurillo.