"Mommy was in the trunk": Lawyer says one of Susan Powell's sons gave damning details of what happened to her

(CBS/AP) GRAHAM, Wash. - One of Josh Powell's sons, who police say were killed by their father Sunday in an apparent murder-suicide, reportedly said that "mommy was in the trunk" when talking about the night that Susan Powell disappeared.

PICTURES: Missing Utah Mother Susan Powell
PICTURES: Missing Utah mom's kids, husband die in alleged murder-suicide

On Sunday, the lawyer for Susan Powell's parents, Chuck and Judy Cox, told the Associated Press the children had started talking to their grandparents about things they remembered from the night in 2009 when their mother vanished.

"They were beginning to verbalize more," said attorney Steve Downing, whose clients had custody of the children. "The oldest boy talked about that they went camping and that Mommy was in the trunk. Mom and Dad got out of the car and Mom disappeared."

Susan Powell, 28, was reported missing Dec. 7, 2009, after she failed to show up for her stockbroker job in Utah. Josh Powell told police he went camping with his two children in the hours before his wife's disappearance.

Powell, who's been the only "person of interest" in the case, had repeatedly denied any involvement in his wife wife's disappearance..

Police say Powell deliberately set off the explosion in a Washington state home Sunday that killed him and his sons, 5-year-old Braden and 7-year-old Charles, shortly after a social worker brought them to his home for a supervised visit.

At a custody hearing on Wednesday, Josh Powell pleaded with a judge to return his children to him saying that he had proven himself, "as a fit and loving father who provides a stable home even in the face of great adversity."

The judge ruled against him, ordering the children to remain with Susan Powell's parents, at least until Josh Powell underwent a psycho-sexual evaluation.

A candlelight vigil was held Sunday night for the boys outside the 7-year-old's school in Puyallup.

Complete Coverage of Susan Powell on Crimesider