VICKSBURG, Mich. (AP) -- A school principal in southwestern Michigan has been charged with sexually abusing a male student.

Kalamazoo County authorities charged Greg Tibbetts with second-degree criminal sexual conduct and several offenses related to using a computer to possess or distribute sexually abusive material.

Tibbetts pleaded not guilty Tuesday. Defense attorney Mike Hills says the charges are "life-altering," so it's a difficult time for Tibbetts. He's principal at Vicksburg Middle School, 20 miles south of Kalamazoo.

Vicksburg Superintendent Charles Glaes tells the Kalamazoo Gazette the boy was a 13-year-old student at Tibbetts' school when the alleged abuse began in 2010.

Glaes says Tibbetts is a "trusted and very capable" principal. He says the charges are "terribly serious."

Tibbetts has been principal for nine years. He was placed on leave in late September.