The cause of death of Christine Thi Woo was determined by the Collin County medical examiner to be suicide by overdose late Thursday after being found dead on March 31. Her body was found in her Honda Pilot SUV with her children alive inside in the parking lot of the Target at the intersection of Preston and Highway 121, a location frequently trafficked by students and teachers.

“When I saw pictures, she looked so normal,” senior Sarah Wieden said. “I am in such shock. Why would you do that to your children?”

Woo’s three children (Lauren, 5; Nathan, 3; Leah, 1) were hospitalized directly after being found and were reported showing signs of dehydration and rashes. Frisco Police reported that they believe Woo did not have deliberate intention to harm her children.

“The investigation…demonstrates that there was no deliberate plan by Woo to harm her three children,” Frisco Police said in a statement Thursday.

The police reported that since Texas CPS is involved, no further information will be released.