Casa Grande police say 35-year-old Connie Villa was arrested on suspicion of one count of first-degree murder and four counts of attempted murder.
Villa is accused of forcing her four children to take prescription narcotics before stabbing her ex-husband and then herself.
According to police, Adam Villa called 911 after he was stabbed during a visit to his ex-wife's residence. Responding officers found the body of 13-year-old Aniarael Macias in a bathroom and Connie with stab wounds, said to have been self-inflicted.
Records show tension had been building between Connie and her husband over the last year.
Adam filed for divorce in December 2012, stating the couple's marriage was "broken." Documents show the divorce went through just two months ago.
Both stated that there was no history of abuse during their time together. But there are documents that suggest Connie was concerned about her children's safety with Adam because she believed he was suffering from Post Traumatic Stress Syndrome, and she wanted him to seek anger management counseling.
Adam stated he didn't want to get counseling, but a judge later made it a requirement.
There is nothing in the court documents that showed any signs there were major issues inside the home.
In fact, documents indicate both parents successfully completed parenting classes.
The three other children are in good condition and are now with their father's family.
Connie was arrested Sunday after being released from a Phoenix hospital.
Police are still working to determine a motive in the poisoning and stabbing.