Former foster parent Garry Prokopishin, 52, is charged with sexually assaulting five teenagers who were once in his care. (Calgary and District Foster Parents Association)

A former Calgary foster parent already accused of numerous counts of sexual assault is facing new charges, police said Monday.

Garry Prokopishin, 52, has been charged with obtaining sex from someone under 18 and sexual contact with a youth by a person in authority.

The assaults are alleged to have occurred when the boy was living in Prokopishin's home, starting in November 2001 — when the boy was 14-years-old — and continuing until September 2005, police said.

It's alleged the man offered the victim money in exchange for sexual acts.

Fifty-five foster children, all boys between the ages of 14 and 17, have lived under Prokopishin and his wife's care in the past 20 years, police said.

In February 2010 and again in November last year Prokopishin was arrested and charged in connection with similar sexual assaults on four other victims that are alleged to have happened from December 2004 to June 2008.

Interviews with other possible victims are being conducted across Canada, police said.

Prokopishin's foster home was suspended in June 2009 when the allegations surfaced. There are no children in the home now.

The Alberta Foster Parent Association named Prokopishin one of its foster parents of the year in 2006.