The highest court in Massachusetts has rejected an appeal by a former high school student who was convicted of planning a Columbine-style attack at his high school in Marshfield.

Joseph Nee was convicted of conspiracy to commit murder and served nine months in prison.

Nee appealed his conviction based on the legal defense of “renunciation,” arguing that he had abandoned the plan by a group of teens in 2004 to blow up Marshfield High School and shoot everyone on a hit list of students, teachers and emergency workers.

In its ruling yesterday, the Supreme Judicial Court said Nee was not entitled to a renunciation defense because he did not acknowledge that he conspired with other students to commit a crime.

The court said Nee failed to reveal and renounce his own crime.