Fifteen months before Samantha Jaume’s accused murderer was arrested, then Terrebone Parish Sheriff’s Office Capt. Darryl Stewart had the suspect in custody, tucked in an interrogation room wired with audio tape recording.

Based on an artist’s sketch and interviews, Stewart thought he had the man St. Tammany Parish Sheriff’s Office deputies wanted for the July 4, 2001, murder of the mother of four.

St. Tammany deputies, however, never responded, Stewart testified Saturday during the first day of testimony in Dominic Robinson’s first-degree murder trial in Covington. In the classic two-way mirrored room while Waggaman’s Robinson was being questioned for an unrelated carjacking in Houma, he admitted to being at Wal-Mart in Covington the day he and Richard Gainey are accused of following Jaume, 25, from the parking lot to her Woodbridge home off Louisiana Highway 22 and killing her.

Robinson faces the death penalty if convicted. Gainey, meanwhile, is slated to testify against Robinson to escape the death penalty charge and receive a sentence between 10 and 99 years for armed robbery. Sentencing is scheduled for Sept. 8.

Back in the interrogation room on Sept. 26, when Stewart questioned Robinson about Jaume’s murder, the conversation screeched to a halt.

“We lost dialogue,” Stewart testified. “The conversation shortened. He stopped talking.”

On Saturday, Stewart testified he contacted the St. Tammany Parish Sheriff’s Office and informed them he may have their suspect in custody. Nobody responded, he said.

“Did you get the response you hoped for?” prosecutor Bruce Dearing asked.

“No sir.”

“Did that bother you?”

“Yes, sir,” Stewart said, adding later, “It was a fact that needed to be looked at and followed up.”

It wasn’t for at least 15 months, he testified.

Roughly two years later, after a broadcast on “America’s Most Wanted,” St. Tammany Parish Sheriff’s Office deputies arrested Robinson for Jaume’s murder. Robinson is accused of killing Jaume with a single gunshot behind her left ear.

He and Gainey are accused of following Jaume home from Wal-Mart in an attempt to steal her 2001 Ford Expedition.

A self-proclaimed heroin addict who is serving a life sentence in Angola for the Houma carjacking, Robinson planned to steal the SUV to buy drugs, prosecutors argued.

That Independence Day afternoon Jaume was buying cds, coloring books and toys for her children Colleen, then 9, and Jason, then 7, as they prepared to take a trip to Florida.

“It was the last day Samantha Jaume was alive,” prosecutor Scott Gardner said in opening arguments.

Jaume, who moved into her dream home from New Orleans to get away from crime a year and a half earlier, had planned to raise her children Colleen, Jason, Amanda, 5, and Bailey, 2, in St. Tammany.

She and her husband, Jason Jaume, had grown up together in Metairie, fell in love and married when he was 20 and she was 17, Gardner said.

Their future together, however, was halted when Robinson pulled in behind Jaume and demanded her car keys.

“Samantha told the kids, ‘Get the keys. Get the keys. Find the keys,’” Gardner said.

During the commotion, Bailey, Jaume’s 2-year-old son, sat still in his car seat.

The keys, left inside on the kitchen counter, led Robinson to force Jaume at gunpoint back inside the raised level home.

Colleen, sensing something was wrong, retrieved a knife from the dishwasher, the prosecuter said.

“Back off or I’ll kill you,” she warned.

Later, Colleen and her sister Amanda hid in a closet, while Jason Jr. fled to a backroom and hid under a desk, calling 911.

During the call “you can actually hear the gunshot that killed his mom,” Gardner said.

But defense attorney Maurice Tyler on Friday tried to zap the emotional connection to jurors for the children who lost their mother. The children, the only eyewitnesses to the crime, had described the shooter as a 6-foot-7 black man.

Standing next to Robinson, Tyler said he was 5-foot-11. Robinson was about an inch taller. He also pointed to Robinson’s tattooed arms, the mole by his nose and mark under his cheek. None of the witnesses described those features, he told the jurors.

That’s because the “real killer doesn’t have that. The real killer isn’t in this courtroom,” he said.

He also argued that no fingerprints or DNA evidence linked Robinson to the murder, despite Robinson giving DNA swabs for analysis.

“It’s not my guy,” he said. “What else can we do? If they came up with another test, we’ll take it right now.

The case, he said, is an “unsolved mystery.”

Tyler also argued against Gainey’s testimony, saying it’s simply a means to save his own life.