DRAMA Unforgotten ITV, 9pm

BBC2, 9pm

Last week, Sunny and Cassie (Sanjeev Bhaskar and Nicola Walker, above) began their latest cold case after a dismembered body was uncovered. They now have four suspects to investigate, which sounds promising, but as regular viewers know, there will be plenty of twists and turns before all is revealed. It certainly doesn’t help that some of the body parts are missing, making pinning down the cause of death impossible.

Working with geneticist Professor Turi King, Stacey Dooley (above) helps to answer people’s burning questions about their family, health or ancestry by visiting a DNA testing clinic. Tonight she meets 75-year-old Bill, who grew up without knowing his American GI father, and 53-year-old Richard, who discovered after his father’s death that they weren’t blood-related.

Channel 5, 9pm The presenter (above) has special access allowing him to go deep inside the Chernobyl nuclear power plant to see the burnt-out remains of Control Room 4 – where you can spend only five minutes before radiation forces an exit. He also explores the deserted remains of the ghost town of Pripyat, which was abandoned after the disaster and has been left untouched for 35 years.