The 16-year-old went missing on the night of Aug. 16 on her way home from a high school graduation party near Truckee, Calif.

A car was found submerged in the Prosser Creek Reservoir and the body inside it was positively identified to be the missing teen on Aug. 21, police said in a press conference

Now, the Nevada County, Calif. coroner's office has released the young girl's cause of death.

on Oct. 13, the coroner's office revealed that she "drowned in lake while in her vehicle." Her manner of death was ruled accidental.

Kiely was last heard from around 12:30am on the day she went missing when she texted her mother, Lindsey Rodni-Nieman, to let her know she was on her way home,

according to authorities. When she failed to arrive, the authorities were contacted and a search began to locate her. 

The group Adventures With Purpose, a Search & Recovery Dive Team dedicated to helping families find missing loved ones, found the submerged car in Prosser Creek Reservoir near Truckee, Calif.

The car was located not far from the campground where the party Kiely attending took place. 

Adventures With Purpose released a statement when Kiely's body was identified, saying, "Please keep the Rodni family in your thoughts and prayers as we are.

Hug your loved ones a little tighter and take the time as you never know when it's your last opportunity to do so."