Authorities: Josh Powell planned deadly fire GRAHAM, Wash. - Authorities say Josh Powell planned the deadly house fire that killed him and his young sons for some time, dropping toys at charities and sending final emails to multiple acquaintances. Powell, the husband of missing Utah woman Susan Powell, died along with his children Sunday. Authorities say they found 10 gallons of gasoline inside the home. A five-gallon can was spread throughout the house and used as an accelerant in the huge blaze. Another can was found by the bodies. They say Josh Powell did send longer emails to some people, including his cousin and pastor, with instructions such as where to find his money and how to shut off his utilities. But none of the emails said anything about what happened to his wife. Lawyer: Powell boy spoke of mommy "in the trunk" Josh Powell, kids die in alleged murder-suicide Did authorities do enough to protect Powell boys? The maternal grandparents of Josh Powell's two sons said Monday that the boys played happily and didn't want to visit their father when the time came for their weekly Sunday visit. But Charles and Judy Cox told KIRO-TV that the grandmother talked them into a court-ordered, supervised child custody visit with their father - a decision she now regrets. When the boys arrived at Powell's Washington state home, their father barred a social worker from entering and then torched the house. All three died. "Look what happened," Judy Cox tearfully told the station. But I knew that they're supposed to be able to see their dad. Charles Cox said he didn't think there was any more the court could have done legally to protect his grandchildren, but he wished there had been. "There were too many warning signs that I feel were known, but due to legal limitations were unable to be acted upon," he said. The Coxes opened their home to news reporters Monday to give a glimpse of the boys' life with them. Charlie, 7, and Braden, 5, had been living with them since last fall, when the state removed them from their father's custody. Josh Powell had long been a person of interest in his wife's disappearance from their home in West Valley City, Utah, two years ago. He claimed he had taken the boys on a midnight camping trip in freezing temperatures when she vanished. Police who arrived at the home to look for the family found two fans pointed at a damp spot on the floor, but no trace of Susan. Her body has never been found, despite intensive searches in Utah and Nevada. Powell maintained custody of the boys as the scrutiny upon him intensified over the years. He moved to his father Steve Powell's home in Puyallup. Last fall, when the elder Powell was arrested in a voyeurism and child pornography case, the state turned the boys over to the Coxes. On Monday, authorities continued sifting through the smoking rubble of the home looking for evidence, and the medical examiner's office was working to determine cause of death. It remained unclear how the deaths might affect the investigation into Susan's disappearance. The Pierce County Sheriff's Office planned an afternoon news conference. On Sunday, the lawyer for Susan Powell's parents said the children had started talking to their grandparents about things they remembered from the night their mother vanished. 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.