Representation. Police cars. ArtisticOperations/Pixabay

A grisly discovery of the bodies of a mother and her three children in a lake in Minnesota has been ruled a murder-suicide by authorities. Police believe the mother chose to kill herself and her children following the suicide of her husband inside their home.

On Thursday, officials with the Ramsey County Sheriff’s Office revealed their findings after over a week of investigating how the bodies turned up in Vadnais Lake, located outside of St. Paul. In a statement posted to their website, the Sheriff’s Office laid out a timeline for how they believe the crime played out.

Last Friday at approximately 10:37 AM, officers with the Maplewood City Police Department received a call from Molly Cheng, 23, who told them that her husband had just shot himself. Arriving on the scene, they discovered the body of Yee Lee, 27, with what they determined was a self-inflicted gunshot.

Later that day at around 4:00 PM, a relative of Cheng's called police again to warn them that she was going to kill herself and her children. Maplewood police issued a statewide alert to “attempt to locate and check the welfare” of Cheng and her children.

Almost two hours later, officers were able to pinpoint Cheng's last known location in Vadnais-Sucker Lake Park in Vadnais Heights. At the scene, located the vehicle in a parking lot at about 6:03 PM and about twenty minutes later discovered several pairs of children's shoes as well as keys to the vehicle on the east shore of the lake.

At 7:32 PM, police recovered a child from the lake but were unable to resuscitate him. The child was determined to be Cheng's son Quadrillion T. Lee, 4, and it was determined he died as a result of intentional drowning. By the next day, police were able to retrieve the bodies of Phoenix Lee, 5, Estella Zoo Siab Lee, 3, and Cheng herself from the lake. All of the children's deaths were ruled homicides and Cheng's was deemed a suicide.

“Our hearts go out to the family, friends, and community impacted by this terrible tragedy,” said Undersheriff Mike Martin. “The Sheriff’s Office is continuing to investigate the circumstances of this incident to provide clarity and closure to the surviving family members.”

Chong Lue Lee, the children's grandfather, told local media that he hoped the children would remain under police supervision after his son Yee's suicide but they were instead released to their mother.

Police defended the decision to return the children to Cheng’s custody as based on the advice of social workers, who they made available to the family after Yee killed himself.