CHICAGO — The conviction rate for sexual offenses reported at six Midwestern college campuses is far lower than the national average, according to a newspaper survey published Friday, and experts say the numbers are part of a larger trend.

Police have investigated 171 sex crimes at the universities in Illinois and Indiana since fall 2005, resulting in 12 arrests and four convictions, according to the Chicago Tribune.

That means law enforcement made one arrest for about every 14 sex crime allegations, and of those arrested, 33 percent were convicted. Nationally, about 1 in every 4 allegations results in an arrest, and of those arrested, 62 percent are convicted.

Russlynn Ali, assistant secretary for civil rights in the U.S. Department of Education, tells the Tribune that the findings at the six schools are consistent with anecdotal evidence her office has gathered from victims.

“I say this, albeit, with a very heavy and saddened heart,” Ali said. “These kinds of data are illustrative of the disturbing and alarming trend we are seeing across this country.”

The schools surveyed were the University of Illinois campuses in Champaign and Chicago, Illinois State University, Northwestern University, the University of Notre Dame and Indiana University.

Three of the schools had zero convictions from their 63 reported cases, and one school had just one conviction.

The newspaper cited the case of a former Indiana student who accused a fellow student of rape after a night of drinking in 2006. Police declined to press charges, and the university eventually suspended her alleged attacker for a year.

She left campus after the Department of Education’s Office of Civil Rights found that the university acted “promptly and appropriately.”