Texas police say two Mississippi children and their grandmother were killed by the children’s mother last month in a triple murder-suicide, Texas media report.

Divorce records indicate that a custody battle may have driven a woman to kill the children, ages 5 and 3, along with her own mother before killing herself.

Police say Karina Sornoz Deitering, 37, committed the crimes on April 27, shooting all three victims, then herself. Police say Deitering shot her 5-year-old daughter, Clara, her 3-year-old son Robert and her own mother, 68-year-old Galina Taypina.

Their bodies reportedly found by the children’s father who spotted them looking through the window of his estranged wife’s apartment in San Antonio. He traveled there after they failed to show up at a custody exchange meeting.

The family is actually from Mississippi, but as their divorce proceedings were being worked and final custody determined, the children were splitting time between the father on the Mississippi Gulf Coast and the mother, who was temporarily living in Texas.

FoxSanAntonio.com reported that just before the killings, the court had determined it was in the best interest of the children to be in the full-time custody of the father and that child support was to stop on May 1.

A funeral for the two children is planned for later this week in D’Iberville, Mississippi.