A former student convicted of helping plan a Columbine-style attack at Marshfield High School has been sentenced to nine months behind bars.

Joseph Nee received the sentence Tuesday, but was credited with three months served. He also got two years of probation.

The 21-year-old Nee was convicted last week of conspiracy to commit murder, but acquitted of two other charges. He had faced up to 20 years in prison.

Nee was one of three Marshfield High students who went to police in September 2004 and reported that another student, Tobin Kerns, was planning to kill students and teachers in an attack similar to the 1999 rampage at Columbine High School in Colorado that left 15 people dead.

Kerns also was convicted in the plot and is serving ten months.