PHOENIX (KTVK) -- Police say the mom of three children found dead in an Arizona home has admitted to killing them.
The Phoenix Police Department tweeted Tuesday morning that the mother is a 22-year-old woman who recently moved to the area from Oklahoma.
“The 22-year-old mother has admitted to harming her three children," said Sgt. Mercedes Fortune of the Phoenix Police Department. She explained that the woman, whose name has not been released, will be booked on suspicion of first-degree murder.
The children -- a 7-month-old girl, a 2-year-old girl, and a 3-year-old boy -- were found around 7:30 p.m. Monday at a Phoenix residence. It's still unclear how they died. That will be up to the Maricopa County Medical Examiner's Office.
Police say they first received an "unknown trouble call" from a relative of the children. When police arrived at the home, they were greeted by three adults -- the mother, the father and another relative, Fortune said.
According to police, the kids were in a living room area just off the front door. “We didn’t have to go look for the children," Fortune said. All three of the children were unresponsive. Officers performed CPR on them. Fire crews then arrived at the home and paramedics also provided first aid. But sadly, all efforts were unsuccessful, and the children were pronounced dead.
During a news conference late Monday night, Fortune said that police were told that the children were "ill" earlier in the day. She also said the children showed no obvious signs of trauma.
"We're trying to determine why this occurred," Fortune said. "Any time you have three children that are deceased ... in that aspect, it is suspicious."
Fortune said the kids lived at the home with their parents and two other adults. At this point, police have not determined what happened in the moments, hours and days leading up to the children's deaths. They are working to determine what prompted the mother's actions.
"As you can imagine, this case is very complex," she said Tuesday morning as police were wrapping up the on-scene portion of their investigation. "There’s a lot of moving parts to it. We are comfortable in saying now that the mother is responsible for the death of the children.."
It was an extremely difficult scene to witness for first responders. Fire crews who responded to the call reportedly did not work the rest of the night due to being traumatized by the incident. "It's very difficult," Fortune said.
Arizona's Family will update this story as we learn more about the investigation.