CALMAR, Alta. - A bartender in central Alberta was charged with manslaughter Friday after one of his customers drank herself to death last fall.

The bartender and his boss at Skip Sports Bar in Calmar - 50 km southwest of Edmonton - have also been charged with criminal negligence causing death in the case of Tammy Kobylka.

Kobylka, 22, died last October of what the coroner termed "acute ethanol toxicity."

Alberta Justice spokesman David Dear said such charges are rare, but "the courts have made it plain that bar owners and staff can be liable for the consumption of patrons."

RCMP Const. Jodi Heidinger said the bar was originally charged under the Gaming and Liquor Act for serving a person who was already intoxicated.

But a year-long investigation resulted in the prosecutor requesting that the original charges be withdrawn and replaced with charges under the Criminal Code, she said.

Several police agencies were involved in this investigation, including the RCMP regional drug section, the forensic investigation unit and the medical examiner's office.

"It was a very detailed and in-depth investigation," said Heidinger, who described Skip's as a regular small town bar on the main strip in Calmar.

A woman who answered the phone at Skip's on Friday declined comment.

"There's no comment from anybody," she said.

Police have also charged SBH Enterprises, which owns the bar, with criminal negligence causing death.

Neither the RCMP nor the Justice Department were able to reveal any details that led to the more serious charges being laid because the case in now before the courts.

Kobylka was pronounced dead at her home in Calmar on Oct. 7, 2007.

Tests showed her blood-alcohol level was five times over the legal limit for driving.

Lynn Kobylka, Tammy's mother, could not be reached Friday, but said at the time of her daughter's death that the young woman and two men were in Skip's from 12:30 a.m. until it closed at 2 a.m.

They then returned to Tammy's home. Kobylka said she has been told the two men left after her daughter began to fall asleep on a couch.

Later, another man in the home woke up, noticed Tammy wasn't breathing and called 911.

Kobylka said her daughter was a hard worker and toiled at two jobs to save up to buy a home.

She said her daughter was an occasional binge drinker who grew up around alcohol.

Alcohol poisoning occurs when a person drinks a lot very quickly, overwhelming the body's ability to protect itself by passing out or vomiting. The body then literally shuts down, sometimes to the point where the drinker stops breathing and dies.

Skip's Bar owner Brian Cameron Bromley, 61, and bartender Derek Allen Tithecott, 33 - both of Calmar - are to appear in court next Thursday in Leduc, just south of Edmonton.