LOS ANGELES, California (Reuters) -- A U.S. sheriff opened an investigation Wednesday into the death of a 28-year-old woman who died after taking part in a California radio contest in which contestants had to drink as much water as possible.

Sacramento station KDND-FM has fired 10 staff members over Friday's competition, called "Hold your wee for a Wii," in which about 20 people tried to out-drink each other without going to the toilet to win a Nintendo Wii games console.

Jennifer Strange, 28, a mother of three, died from suspected water intoxication after coming second. She was reported to have drunk about seven quarts of water in a bid to win the Wii for her children.

After the contest she called in sick at work and was found dead at her home about five hours later. (Full story)

Water intoxication, also known as hyperhydration or water poisoning, is potentially fatal and can cause irregular heartbeat, fluid in the lungs and swelling of the brain.

A spokesman for the station's parent company, Entercom/Sacramento, said 10 staff members, including several on-air DJs, had been fired over the incident.

"They are no longer with the company for violating the terms of their employment agreements with the station," said the spokesman, without elaborating on contract details. "This is part of an ongoing, thorough investigation."

The Sacramento County Sheriff's Department later Wednesday said it had decided to open an investigation into Strange's death.

"We have new information that has come to light from audio tapes of the show," said spokesman Sgt. Timothy Curran.

"We have decided we will open a death investigation which will take weeks and on conclusion our findings will be forwarded to the local district attorney to decide whether to lay criminal charges."

The Sacramento county coroner has yet to rule as to the cause of death but has said Strange's death was "consistent with a water intoxication death."

"We have not heard from the sheriff's department but we will of course cooperate with their investigation," said Charles Sipkins, a spokesman for Entercom/Sacramento.

In an online recording of the show, the DJs can be heard making comments joking about people dying from water intoxication, even discussing a case in Northern California two years ago in which student Matthew Carrington, 21, died after drinking too much water during a fraternity stunt.

One of the DJs even admitted they maybe should have done some research before the contest.

One female caller, who identified herself as Eva, also phoned in to warn the radio station that drinking too much water can kill.

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