We see how criminals are cashing in on the popularity of cycling – and how one cyclist is using the power of social media to take matters into his own hands and fight back against bike thefts. He has helped recover more than 500 stolen bikes, returning them to their rightful owners.We also feature the story of a 73-year-old motor mechanic who had his van broken into. A collection of tools that had taken a lifetime to build up were stolen, but the local community rallied round to support him. Across the UK, four out of five tradespeople have had their vans broken into and their tools stolen. It's a crime that has a huge impact on many businesses. We look at how technology such as body heat sensors are helping to crack down on van thieves.Also on the programme, a new DNA technique helping forensic artists to sketch the faces of criminals.