Dallas ? A suburban Dallas mother accused of strangling her two young children told a 911 operator she killed them because they were autistic and she wanted “normal kids,” according to a tape released Wednesday.

Irving police released the recording after Saiqa Akhter was charged with one count of capital murder in the strangling of her 5-year-old son, Zain Akhter, at the family’s apartment Monday night. Police spokesman David Tull said another capital murder charge is pending in the slaying of her 2-year-old daughter, Faryaal Akhter, who died Tuesday night.

Police say the mother called 911 after attacking the children. In the recording, the woman identifies herself as Saiqa Akhter and repeatedly tells the operator she killed her two children, describing how she first tried to poison them, then later strangled them with some type of wire. At one point during the recording, the woman hangs up and the dispatcher calls her back.

“I killed them. I killed both of them,” she told the operator.