Jonathan Hearn took the witness stand late Tuesday afternoon and testified how he and his former lover, Sabrina Limon, hatched a plot to kill her husband at his workplace in Tehachapi so they could be together.
Hearn's comments during Limon's preliminary hearing at times elicited gasps from the audience, particularly when he said he poisoned a neighbor's dog in preparation to carrying out a poisoning attempt on Limon's husband.
He said he gave the "pretty obnoxious" dog a piece of salmon laced with arsenic trioxide.
"About three days later, I didn't notice the neighbor dog being obnoxious anymore," Hearn, a former Redlands firefighter, told the court.
His testimony will continue today, and, after all witnesses are heard from, Judge John R. Brownlee will determine whether the prosecution has presented enough evidence to order Limon, 37, to stand trial on charges including first-degree murder.
Hearn, 26, pleaded guilty last month to voluntary manslaughter and other charges in the August 2014 killing of Limon's husband. He accepted the plea agreement in exchange for the dismissal of a murder charge, and for a determinate prison sentence of 25 years and four months.
As part of the plea deal, he agreed to testify against Limon, and to apologize to the victim's family.
On Tuesday, Hearn described how he met Limon at her job at a Costco in 2012, and how their friendship soon led to a sexual relationship. In 2014, they began talking about having a future together.
To achieve that goal, Limon's husband had to be removed from the picture.
Hearn testified that he and Limon discussed the possibility of her getting a divorce, but she shot down that idea because she didn't want to deal with child custody issues, and she was afraid many of the friends she and her husband shared in common would side with him.
She and her husband, Robert Limon, 38, lived with their two children in Helendale, a small, unincorporated community in San Bernardino County.
According to Hearn, she also said her husband would be inconsolable without her.
"She said he would probably rather be dead than divorced," Hearn testified.
Prosecutor Eric Smith asked Hearn where these discussions led.
"Ultimately, to (Robert Limon's) death," Hearn said. "To the murder of Robert."
Through hundreds of discussions, they eventually hit on the idea of killing her husband, Hearn testified. He said they considered staging a car accident or a fire, but decided on poisoning because they thought it might go undetected.
Hearn testified he chose arsenic because it's highly poisonous, works quickly and causes some flu-like symptoms. He purchased the poison online using a prepaid credit card under an alias, and had it delivered to his grandparents' art studio.
The plan was to lace a batch of banana pudding and vanilla wafers with arsenic, then have Sabrina Limon send the dessert to work with her husband.
They later aborted the poison attempt on Limon's husband over fears of getting caught, court documents say Hearn told detectives. He is expected to testify to that detail, and to the shooting of Limon's husband, today.
Limon did not appear to look at Hearn during his testimony. She sat hunched over, her head down through much of Tuesday's proceedings.
Also during Tuesday's hearing, Kern County sheriff's Detective Robert Meyer testified how he fed Sabrina Limon false information regarding leads he was pursuing in her husband's death.
He said he used the ruses to make Limon and Hearn paranoid and incriminate themselves during conversations on their home phones and cellphones, which detectives had wiretapped. Investigators had early on honed in on Limon and Hearn as suspects and requested the wiretaps near the beginning of the investigation.
Limon acted as Meyer expected. She contacted Hearn about 10 minutes after receiving one of the detective's calls the evening of Nov. 17, 2014, Meyer testified.
In a recording of the call played in court, Limon told Hearn about the suspect description Meyer had given her, which was similar to Hearn, and that the suspect possibly had the first name "Jon."
A long silence followed on the recording, then Hearn and Limon began discussing who could have given the detectives that information, whether Meyer was telling the truth and, after hearing a clicking noise on the line, whether their calls were being recorded.
"They might have nothing," Hearn said in the recording. "They might have everything."
He was arrested the next day.
Sabrina Limon was originally arrested with Hearn in November 2014, but released shortly afterward without being charged.
She was rearrested Jan. 6 in Camarillo, after Hearn agreed to testify against her. She faces a life term in prison if convicted of the murder charge.
Her attorney, Richard Terry, noted Hearn never implicated his client in the killing until the plea deal was offered, giving him an opportunity to one day be released from custody.
Sabrina Limon told Hearn where her husband was working and his schedule on the day of the killing, according to court documents. Investigators said she and Hearn talked for 80 minutes on the phone after her husband left for work that day.
The documents say surveillance cameras captured images of Hearn leaving the Burlington Northern Santa Fe Railway complex, where Robert Limon worked, after the shooting.
Court proceedings are scheduled to resume 9 a.m. today.