The mother of two children who were found dead in a Tempe, Arizona, apartment has been charged with two counts of first-degree murder in their deaths, police said Saturday.

Police found a 9-year-old girl and a 7-year-old boy dead in the apartment after the children’s mother flagged down an officer about 7 a.m. and told him “she was hearing voices telling her to kill her kids,” Tempe Police Sgt. Steven Carbajal said during a news conference.
The children had “obvious signs of physical trauma,” according to a release from Tempe police.
“It was something very traumatic for our officers to walk into,” said Carbajal, even though they are trained to deal with these situations.
Yui Inoue, 40, was arrested and will be booked into the Maricopa County Jail, Carbajal said. CNN has not been able to determine if she has legal representation or when she will appear in court.
Police had been at the apartment earlier that day, just after midnight, because of a domestic dispute, Carbajal said. The news release said the dispute was between the husband and the wife.

“At that time, everything seemed to be OK. The parties were separated, the children were found to be in good condition, OK and alive at that point,” he said.
“The children were safe in their bed” when officers left, Carbajal said. “It didn’t seem like there was an immediate threat to the children.”
The father was not home at the time of the incident, and he was not a suspect, Carbajal said. The father “just broke down” after being informed of the children’s deaths, Carbajal added.
“This should have never happened,” he said. “What the children experienced is just horrific, really.”
The city’s crisis response team and the police department’s peer support group were working with the officers who were at the scene.
“There’s a lot of officers that were involved in either a call last night or this morning, which was two different groups of officers, that are very emotionally overwhelmed by this, and we’re trying to get them the support they need to get through that as well,” Carbajal said.
“For those that witnessed the scene, for those that saw the children, it’s something that’s going to stay with them for the rest of their lives,” he said.
CNN’s Aya Elamroussi contributed to this report.