WOBURN, Mass. (AP) — A former Missouri radio reporter gave his wife a lethal dose of antifreeze, then delayed taking her to a hospital for 10 hours because he wanted to collect $250,000 in life insurance money, a prosecutor told a jury yesterday as his murder trial began.

James Keown's defense attorney told the jury that no one knows how Julie Oldag Keown ingested ethylene glycol — a chemical found in antifreeze — and suggested she may have committed suicide or accidentally consumed the chemical.

Keown, 34, is charged in the September 2004 killing of his wife of eight years. Prosecutors say he slowly poisoned her over several months by lacing her Gatorade with antifreeze, before giving her a fatal dose on Sept. 4, 2004. Julie Keown, 31, slipped into a coma and never regained consciousness. She died at Newton-Wellesley Hospital four days later.

In opening statements yesterday, Assistant District Attorney Nathaniel Yeager said Keown killed his wife after he was fired from his job, the couple's financial problems worsened and a string of lies he had told his wife began to catch up with him.

"Murder by deception — that is what the evidence in this case will prove," Yeager said.

Keown's attorney, Matthew Feinberg, acknowledged Julie Keown ingested a fatal dose of ethylene glycol, but said "we may never know" if it was suicide or an accident.

"The Commonwealth doesn't know how it happened and neither do we," Feinberg said. "There is no direct evidence linking James Keown to his wife's tragic death."

The couple, who met while attending college in Missouri, moved to Waltham in January 2004. Yeager said James Keown told his Kansas City employer — an educational consulting company — he had been accepted at the prestigious Harvard Business School and asked if he could work remotely from the Boston area. The company agreed, and the Keowns relocated to Massachusetts.

Six months later, though, Keown was fired when his boss discovered he had lied about being accepted to Harvard and had stolen a Web site design he was asked to develop for the company, Yeager said.

Julie Keown, a registered nurse, began showing signs of poisoning in the spring of 2004. Yeager said she was hospitalized in August after her speech became slurred and she had difficulty walking. After three days in the hospital, doctors told her she was suffering from a kidney ailment and she was released.

Two weeks later, James Keown spoke to an on-call doctor at Newton-Wellesley Hospital and said his wife was ill again. The doctor told Keown to bring his wife to the hospital right away, Yeager said.

But Keown waited more than 10 hours to take her to the hospital, and by that time, his wife could not speak or walk, Yeager said. She slipped into a coma shortly after arriving at the hospital.

Keown was not charged in his wife's death until more than a year later, when he was arrested in Jefferson City, Mo., where he was a reporter and talk show host at radio station KLIK-AM.

Yeager said in the weeks before the fatal dose, James Keown used his computer to research poisons, including arsenic. Two days before Julie Keown entered the hospital the first time, James Keown's computer showed he did a search using the words, "ethylene glycol death human," Yeager said.

But Feinberg said Julie Keown became despondent after she was hospitalized in August, when doctors discovered she had an underlying chronic kidney disease that had been undiagnosed for years. He said that on Sept. 4, James Keown used "terrible judgment" in not taking his wife to the hospital right away, but said he delayed because Julie Keown told him she didn't want to go.

Feinberg said no antifreeze was found in the Keowns' home and there is no evidence James Keown poured antifreeze into his wife's Gatorade.

"It's a story and nothing more," he said of the prosecution's claim.