CALGARY -- A Calgary judge is allowing a police therapy dog to sit with two child witnesses in an upcoming sex abuse trial.

Crown prosecutor Rosalind Greenwood said it may be the first time in Alberta -- even in Canada -- that a dog is to replace a court support worker.

"When you have a support worker in a room with a child there is always the possibility that the defence could suggest that there was something the support person did to taint the evidence of the child, but with a dog -- it is a dog," she said Wednesday. "There is no risk of that possibility happening."

The black Labrador retriever, named Hawk, joined Calgary police last year.

The case involves a man charged with sexually assaulting his seven-year-old daughter.

Greenwood said the dog has already met with the two child witnesses.

The girl and her brother are to testify when the trial begins in December.

She said Hawk will be a comfort to them.

"If you have ever had a dog you would understand," she said. "Dogs tend to relieve stress from people. There is almost an unexplained relaxation that you get with dogs."