May 6 (Bloomberg) -- Authorities arrested 75 students, including a criminal-justice major, at San Diego State University, on charges stemming from the sale of cocaine, marijuana and ecstasy, the Drug Enforcement Administration said.

The arrests, 18 of them today, were the result of an undercover investigation that began after a San Diego State student died of an overdose in her bedroom a year ago, the DEA said today in a statement. Seven fraternities were targeted in the investigation, Operation Sudden Fall, in which 21 non- students also were arrested.

``To our knowledge this is the largest bust of this kind,'' said Jonathan Kassa, the executive director of Security on Campus Inc., a nonprofit campus crime-watch group based in King of Prussia, Pennsylvania.

A total of 23,080 college students in the U.S., or 6.6 percent more than two years earlier, were arrested on drug charges in 2006, according to the latest figures on a U.S. Justice Department Web site.

Kassa said the next-largest university drug sweep known to his group involved the University of Virginia in Charlottesville in 2003. Authorities there indicted 33 people, including eight students, according to the Cavalier Daily, the student-run newspaper. University spokesman Daniel Heuchert didn't immediately return a phone call seeking comment today.

At San Diego State, DEA agents and university police infiltrated ``student drug distribution cells,'' the authorities said. A member of the Theta Chi fraternity sent a text message to his customers, alerting them that fraternity brothers would be unavailable to sell cocaine because they were going to Las Vegas for the weekend, the DEA said. He also gave cocaine prices.

Homeland Security Major

One student charged with dealing cocaine was a month from getting his master's degree in homeland security, according to the statement. A criminal-justice major who was arrested was charged with having 500 grams of cocaine and two guns, the DEA said.

``If guilty, they have ruined an untold number of lives,'' said San Diego State President Stephen L. Weber, in a separate statement. ``Today's arrests are a big step forward toward a safer environment for our students, faculty, staff and neighbors.''

Most of the arrests took place during the past year, the university said in a statement on its Web site. All of the arrested students were suspended, and won't return to class or take exams ``until completion of due-process review,'' Weber said. Students living in university-managed housing were evicted, he said.

Pervasive Peddling

Agents ``confirmed that a hierarchy existed for the purpose of selling drugs for money,'' according to the statement.

``This operation shows how accessible and pervasive illegal drugs continue to be on our college campuses, and how common it is for students to be selling to other students,'' said San Diego County District Attorney Bonnie M. Dumanis, in the statement.

While the investigation was under way, a 22-year-old student from Mesa College in San Diego died Feb. 26 of a cocaine overdose in a San Diego State fraternity house, the DEA said.

The university said the law-enforcement authorities believe they have arrested ``the majority of those involved.'' The school said there may be more arrests.

Agents made more than 130 drug purchases and seizures during five months, the DEA said. Among the drugs seized were 4 pounds of cocaine, 50 pounds of marijuana, 48 marijuana plants and 350 ecstasy pills. Police also confiscated one shotgun, three semi- automatic pistols, three sets of brass knuckles and $60,000.

To contact the reporter on this story: Brian Kladko in Boston at bkladko@bloomberg.net.

Last Updated: May 6, 2008 18:24 EDT