FORT COLLINS, Colo. —  The Colorado State University (search) chapter of a fraternity where a 19-year-old woman was found dead was shut down the same day the school's Greek system adopted rules barring alcohol from sorority and fraternity houses and some parties.

The Sigma Pi (search) house was closed Thursday after university officials said an investigation turned up violations of alcohol rules during the past year.

Samantha Spady (search), a sophomore business major from Beatrice, Neb., was found dead in a lounge at the fraternity house Sunday. Police suspect drinking contributed to her death and have ruled out foul play. The Larimer County coroner had not determined the cause of death.

Investigators believe she had been dead for about 12 hours before a fraternity member found her body.

CSU officials said a university investigation revealed the fraternity chapter had violated alcohol rules by holding unauthorized parties, serving alcohol at the fraternity house and serving alcohol to minors.

"The primary issues are the alcohol and rules violations," said Anne Hudgens, CSU executive director of campus life. "The decision got made in the context of the whole history."

The student-run councils that oversee CSU's Greek system announced policy changes Thursday that include banning alcohol at parties not held at facilities licensed to serve alcohol.

Alcohol will not be allowed in sorority and fraternity houses, said Maura Ryan, president of the Panhellenic Council. The change will affect 11 fraternities that had allowed members of legal drinking age to have alcohol in their houses.

Eight other fraternities and all eight sororities already banned alcohol from their properties, Ryan said.