A forensic pathologist working for the defense yesterday testified that he believes Garrett Eldred Wilson's infant son died after a seizure and not by smothering, as prosecution experts have contended.

Miles James Jones's opinion differed sharply from the conclusions of state medical examiners that ultimately led Wilson to be charged with killing his two children to collect $190,000 from life insurance policies. Wilson, 43, is being tried in Montgomery County Circuit Court on first-degree murder in the 1987 death of his 5-month-old son, Garrett Michael.

The Frostburg man is scheduled to stand trial in September in Prince George's County on first-degree murder in the death of Brandi Jean Wilson, a 2-month-old girl who prosecutors contend was smothered six years earlier in 1981.

Jones testified that he based his judgment on Garrett Michael's death from information provided by Wilson's defense attorneys, material that did not include photographs of the boy or statements from the child's mother. He concluded after a 15-hour review that the infant had died of undetermined causes, possibly a seizure that triggered his brain to swell.

"Anyone who wanted to classify it as SIDS or homicide would be wrong," he said.

Jones could not determine what caused the normally healthy infant's seizure but said it is possible that Garrett Michael was suffering from a viral infection. He testified that he believed Brandi Jean died of sudden infant death syndrome.

Initially, medical examiners attributed the deaths to SIDS and ruled the manner of deaths natural.

But Maryland Medical Examiner John Smialek, coupling evidence gleaned from a renewed investigation into the deaths with heightened scientific understanding of SIDS, changed the cause of Brandi Jean's death in 1997 to probable suffocation, or smothering, and ruled the manner of her death "undetermined."

Smialek, who testified Tuesday, also changed Garrett Michael's cause of death to smothering but ruled the manner was homicide.

On Monday, Charles P. Kokes, the medical examiner who performed the 1987 autopsy on Garrett Michael, estimated that the probability of two children in the same family dying of SIDS--with one child's brain being swollen--is about 1 in 100 million. In an unusual ruling, Judge Ann S. Harrington allowed jurors to hear testimony about both deaths because they share so many similarities.

Jones, like the other experts, agreed with the autopsy's finding that Garrett Michael's brain was swollen at the time of death, an unusual occurence in SIDS cases, some experts say.

Jones's testimony dominated the defense's case yesterday, as Wilson's attorney, Barry Helfand, said his client could not afford many expert witnesses. The prosecution rested its case Tuesday, and closing arguments could begin today.

From the trial's start, Helfand conceded that to convince a jury of Wilson's innocence would be tough. Yesterday, he described the trial as one of the most challenging he's faced.

"It's one of the most challenging . . . because it has such natural emotion for all of us," he said. "You're talking about two babies, and you put them on a wall and said they're dead? What do you expect people to think, or do?"