I grew up in the area where these murders occurred and, for some reason, this case has remained with me. At the time, my mum worked at a women's clothing store in the shopping centre were the girls reportedly attended (I have faint memories as a kid driving with my dad in an old Ford Falcon during nighttime to pick my mum after work). The birthday gift that Wendy's sister mentions in the video was a blouse, based on information I found on the internet and old newspaper articles. So, accordingly, I deduced the plausibility that Wendy and Donna shopped at the store where my mum worked. I asked my mum about this a few years back but, alas, she has no memory of such an occurrence, nor does she recall the homicide case as such.
The Toronto Homicide link for this cold case can be found here. The attending newspaper article for the video above is here. Also, there is a detailed public discussion thread/forum covering many aspects of the case here.
A new year has just arrived and it has been 37+ years since the homicides happened. Perhaps the reader might take a few moments to say a Hail Mary for Wendy/Donna and their families, with the additional intention for Toronto Police to solve this cold case.