Officials from the University of Maine in Orono say a fire that damaged the Raymond H. Fogler Library on Wednesday night was a case of arson.

A small fire between the first and second floors was reported just after 9 p.m. Wednesday and damaged about 50 books. The building was evacuated and no one was injured.

On Thursday, university officials said the fire is being investigated as arson by the Office of the State Fire Marshal. A reward of $2,500 for information leading to the arrest and conviction of anyone responsible is being offered by the UMaine Police Department and Division of Student Life.

The library is closed until further notice.

The library, which opened in 1947, is home to more than 1 million volumes. It was renamed in 1962 after University of Maine graduate and Assistant Secretary of the Navy Raymond Fogler.