When a pair of discarded jeans was discovered near the river on 31 December 1989, containing an ID card for a girl called Felicia Stephens, police began an aerial search of the surrounding area. On 2 January 1990 a helicopter spotted what appeared to be a naked female body, lying on the ice surface of the river, near a bridge in the forest. The body was not Felicia Stephens but that of a missing prostitute, June Cicero, who had also been mutilated post-mortem, as well as sawn practically in half.
Most importantly, the helicopter spotted a man standing on the bridge next to a small van, who appeared to be either masturbating or urinating. Fortunately for the authorities, Shawcross had, as speculated, returned to the scene of one of his crimes to relive the pleasure of the attack.
Patrol teams on the ground were alerted to track the vehicle, which had made off at speed, and finally tracked down Shawcross via the registration, which was in the name of his girlfriend, Clara Neal. When approached, Shawcross agreed to assist the police with their enquiries. When they asked for his driver's license, he admitted he did not have one and then revealed that he had been in jail for manslaughter.
Police were confident they had their killer and further questioning revealed the earlier child deaths and a grandiose account of his Vietnam War service, which was later discounted. A photo taken of him, during the initial questioning, soon confirmed his identity as 'Mitch' and official enquiries unearthed the reason for Shawcross’ sealed record that had prevented the police from tracking him down sooner.
Still, police were unable to get Shawcross to admit to the murders, until they confirmed that a piece of jewellery that he had given to Clara Neal had belonged to June Cicero. When police threatened to implicate her in the killings, Shawcross capitulated and admitted to most of the murders, giving detailed excuses about why he had been 'forced' to kill each one. He even admitted to the killing of two undiscovered bodies, those of prostitutes Maria Welsh and Darlene Trippi, leading investigators to their bodies. His formal confession was nearly 80 pages long.