TALLAHASSEE, Fla. -

State officials say an investigation failed to turn up causes for a high number of erasures on last year's Florida Comprehensive Assessment Test at four schools.

A report released Friday by the Department of Education says investigators did find teachers at Greensboro Elementary School in rural Gadsden County coached or interfered with student responses on the 2011 FCAT.

But evidence did not indicate they altered students' responses at any of the schools.

The department's inspector general's office also investigated high numbers of erasures at the Charter School of Excellence in Broward County, Chaffee Trail Elementary in Duval County and Jefferson Elementary in Jefferson County.

The investigation was launched after a sophisticated analysis used for the first time found an extraordinary number of erasures at several schools.