Joseph Dumas looks to the gallery during opening arguments in superior court in Bangor on Monday, April 27, 2009. Dumas died in prison on Thursday. Credit: Kevin Bennett

WARREN, Maine — An inmate serving a 30-year sentence for murder died Thursday night at Maine State Prison, authorities said.

Joseph Dumas, 60, formerly of Prentiss, died around 7:20 p.m. at the prison and was attended to by staff, according to theMaine Department of Corrections, which did not say the cause of death.

In November 2007, Dumas shot his best friend five times in the back and the head after a cocaine binge. His scheduled release date was March 11, 2036.

This is the third state inmate to die at the prison this month. An inmate serving time for unlawful sexual contact died there on Dec. 3, just one month before his scheduled release. Another inmate serving a 75-year sentence for murder died there on Dec. 5.