This episode contains distressing themes and descriptions of violence.

This podcast is intended for a mature audience.

Listener caution is advised.

Passengers gazed through windows out into the darkness as they travelled through the highlands on a cold November night.

The train tracks ran parallel to the A-9 Road.

An orange glow stood out among passing headlights and billowing grey smoke could be seen in the air. It was coming from a car on a lay-by around 10 miles from Inverness near Dalmer Gary.

The driver of a passengerless bus pulled in to investigate the flames flickering over the

embankment.

As he got closer, the driver found a blue BMW engulfed in flames.

Emergency responders were relieved to find there were no casualties. The car had been abandoned. Puzzlingly,

the vehicle was traced back to a mother who had left Inverness with her three-year-old son hours earlier.

What initially seemed to be a burnt-out vehicle left after a joyride turned out to be so much more.

It remained a mystery for over four decades.

Welcome to Season 9, Episode 15 of They Walk Among Us, a podcast dedicated to UK True Crime.

Christina Catherine MacDonald, who went by Rini, and her older sister Morag were raised in Buley, a small village outside

in Venice, Scotland. Morag, who trained to become a registered nurse after leaving school,

later said of her younger sister. She was always attractive and fun and was a great Highland

dancer. She was a very decent person.

She was very bright at school, but she didn't ever go as far as she could. Rini was working

in a boots chemist when she met Gordon McCray, an ambitious construction worker who planned

to set up his own firm.

Rennie had decided not to go to university as none of her school friends planned on attending,

...