When sisters Mildred Bowman, 62, and Alice Wardle, 68, flew to Benidorm on July 30, 2005, they were ready for a sun-soaked holiday in the Costa Blanca. Staying at the Levante Club Apartments, they made plans to meet Alice's daughter and her family the next day.

But when the sisters never showed up, concern quickly turned to panic. Their loved ones searched tirelessly, retracing their steps through their favourite spots - until the hotel manager delivered devastating news 4 days later.

Mildred and Alice had been found dead in their holiday apartment.

What had happened to the two sisters?

And how did their dream vacation turn into a nightmare?