Russell Rodman, 59, admitted to assaulting three boys while he was volunteering at churches in Calgary in the '80s and '90s. (CBC)

A man from High River, Alta., pleaded guilty to abusing three boys when he was a Baptist church volunteer in Calgary.

Russell Louis Rodman, 59, pleaded guilty to sexual assault, gross indecency and sexual contact Monday, but reserved his plea on several other charges.  

His victims were between the ages of 11 to 14.  

The incidents took place between 1981 and 1995.

Rodman will be sentenced on April 8, 2013.  

His son, Greg Rodman, told CBC News in February that his father had recently confided in him that he was struggling with a desire for young boys.  

With help from a family friend, Greg was able to convince his father to go to police .  

"People do terrible things," said Greg Rodman at the time.  

"So those things are true of my dad too, but he's my dad. It's difficult. I mean, life has changed and will never be the same."