The 75-year-old pastor and founder of a Medford church and the country's largest Christian rock festival was sentenced to 18 years in prison Friday after sexually assaulting four minors and having "inappropriate interaction" with another over a 16-year period.

Harry Thomas was the pastor of Come Alive Church in Medford and the co-founder of the Creation Festival, perhaps the largest Christian music festival in the country.

Thomas pleaded guilty in February to one count of first-degree aggravated sexual assault, three counts of second-degree sexual assault and one count of second-degree endangering the welfare of a child.

But his attorney, Robin Lord, told the Courier-Post this week that the plea would be "a death sentence." An attempt to withdraw the guilty plea led to Judge Jeanne Covert rescheduling his sentencing.

Covert later denied the motion to withdraw the plea.

Burlington County Prosecutor Scott Coffina said in a statement that the court proceeding showed "the unmasking of a true Dr. Jekyll and Mr. Hyde."

"An individual who professed to be a man of faith and who has made many positive contributions to strangers committed the ultimate act of betrayal against family members who loved and trusted him," Coffina said.

"There is no sentence that can approximate justice in light of this defendant's despicable acts against these children, but it is gratifying that the victims have been spared the pain of a trial and the defendant almost certainly will spend the rest of his life in prison, where he never can harm a child again," the prosecutor said.

Thomas' sentence contains no parole eligibility. He will serve it at the Adult Diagnostic and Treatment Center, a corrections facility for convicted sex offenders in the Avenel section of Woodbridge.

Joe Brandt can be reached at jbrandt@njadvancemedia.com. Follow him on Twitter @JBrandt_NJ. Find NJ.com on Facebook. Have a tip? Tell us. nj.com/tips