CLARKSTON, Wash. (AP) — A woman shot three of her children, killing one of them, then used the gun to kill herself, a sheriff said Saturday.

Elizabeth Duman, 31, and her 18-month-old son Abraham were found dead at their hillside home Thursday and two others of her eight children were found with gunshot wounds.

"At this time, the evidence indicates the deaths and injuries are the result of Elizabeth using a firearm," Asotin County Sheriff Ken Bancroft said in a statement Saturday.

Sheriff's Lt. Dan Hally said Saturday that investigators were still trying to find a motive for the shootings. He said they did not know if Duman had sought mental health counseling.

Ruby Rose Duman, 3 months, remained in critical condition and her 3-year-old brother, Johannes Duman, was in serious condition Saturday at a hospital in Spokane, authorities reported.

Hally said earlier that officers went to the home Thursday after receiving a call from William Duman, 33, who said he had found the bodies of his wife and child. He was not there at the time of the shootings, Hally said.