This series looks at murders that were callously planned and premeditated, with the 999 emergency calls originating from the killers themselves, who concocted elaborate cover-up stories to avoid justice.
There are no TV Airings of 999: Killer on the Line? in the next 14 days.
Add 999: Killer on the Line? to your Watchlist to find out when it's coming back.
Check if it is available to stream online via "Where to Watch".