Two children found sitting by the side of Interstate 90 in western Idaho Tuesday told sheriff’s deputies that their mother had left them there after running out of gas, officials said.

Kootenai County Sheriff’s Office said in a statement that the boys, aged three and six, said their mother had walked them to the spot on I- 90 where they were found. The kids said they had been taken there when it was still dark and raining.

She then took a ride to a gas station between 6:30 a.m. and 7:30 a.m. local time (8:30 a.m. and 9:30 a.m. ET), the statement said. A construction supervisor working nearby found the children at about 9:10 a.m. local time (11:10 a.m. ET). 

'Argument with her boyfriend'
The woman was arrested on a negligent driving warrant at a house in Spokane Valley, Wash., on Tuesday night after deputies received a tip-off that she was there, NBC station KHQ reported. Kootenai and Spokane counties are on either side of the state line.

KHQ said the mother would most likely face more charges in Kootenai.

The sheriff’s office statement said the woman told the person who gave her the ride that “she had been in an argument with her boyfriend and just needed to get to a phone to call for a ride.”

The children – after being cleared by emergency medical providers – were placed in foster care.

KHQ reported that the woman was seen with her children at a Walmart near the state line Monday night. Someone called police saying she was acting strangely and she was checked out by medics.

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Updated at 4:17 p.m., ET: SPOKANE, Wash. -- Authorities in eastern Washington say they have found the body of a 22-year-old fugitive being sought in the killings of a woman and her two young sons.

The body of Dustin W. Gilman was discovered Monday morning in the Wandermere area north of Spokane, The Spokesman-Review reported.  Authorities did not say how Gilman died.

Police say Gilman was wanted in connection with Friday's killing of 32-year-old Tracy Ann Ader and her 8- and 10-year-old sons at their home, where Gilman had been staying as a family friend.

Tracy Ader's husband was in the hospital at the time with a medical condition.

Police say Gilman took off in Ader's 2007 Nissan Pathfinder, which was found Sunday afternoon at a convenience store parking lot in Spokane.

According to the Spokesman-Review, the vehicle was located a few blocks from the home of Gilman’s father, Larry Gilman. Police said a search of the senior Gilman’s residence came up empty.

Larry Gilman said he had been in contact with this son on Saturday. He told investigators that he’d spoken to his son on the telephone and heard a gunshot, according to the Spokesman-Review. Larry Gilman said he believed his son had killed himself.

Police responding to a 911 call about a dead body in a home found three bodies instead.

Dustin Gilman had been living with the Aders at their home for several months, sharing holidays and caring for the boys, the Spokesman-Review reported.

“They were just the sweetest boys ever,” Melody Ponsness, Tracy Ader’s cousin, told the Spokesman-Review. “They always gave you a hug before you had to go back home. It’s hard to find words. It’s just so shocking.”

The Associated Press contributed to this report.

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Updated 12:57 p.m. ET: SPOKANE, Wash. -- Police have identified a "person of interest" in the homicide investigation of a woman and two children whose bodies were found in a home in north Spokane.

Spokane police say they are looking for 22-year-old Dustin W. Gilman, who is thought to be driving a silver 2007 Nissan Pathfinder.

On Friday, police spokeswoman Jennifer DeRuwe said police were looking for a "suspect" believed to be in a domestic relationship with the three dead.

Maj. Frank Scalise described it as "a potential domestic violence" situation.

The victims' names, ages and cause of death were not immediately released. DeRuwe said she couldn't specify the victims' relationship to each other.

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