VENICE, Fla. (WFLA)—A 44-year-old mother of four drowned after driving her vehicle into a Venice pond last year, police said.

Tracey Rieker went missing from her home on Sept. 30. Her husband, Christian, told WFLA she had been in a manic state, and left their home without her phone or wallet. On Oct. 10, her body was fond in a submerged vehicle in a pond near their home.

An autopsy performed in October confirmed her cause of death was drowning, police said Wednesday. No foul play is suspected.

Police said Rieker had been suffering from an untreated mental condition and was displaying erratic behavior before her death.

“At this time, it is undetermined if Tracey drove into the lake as a conscious deliberate act, or if it was an unintentional consequence of her alered mental state,” police said in a news release. “For this reason, the medical examiner has classified the manner of death as undetermined.”

The investigation into Rieker’s death has been closed, police said.