By the end of January 1978, police were beginning to wonder whether the Ripper had been scared off by his unsuccessful attack on Marilyn Moore. What they did not know at the time was that he had in fact killed again on the night of 21 January, but the severely mutilated body of Yvonne Pearson would not be found until the end of March. Any hopes police may have had were soon put to an end in the first week in February, when another of the Yorkshire Rippers victims was found.
Helen and Rita Rytka were the twin daughters of an Italian mother and Jamaican father. At the age of eighteen, when Helen was killed, they lived together in a miserable room next to a motorway flyover in Huddersfield. Although they both worked as prostitutes, they had dreams of a much better life in the future. In the meantime they would continue to work the streets of Huddersfield red-light district as a pair. To ensure each other's safety, Helen and Rita agreed that they would always take the car number of every client and meet back at an appointed time after twenty minutes, a system which had worked well for them until the snowy night of Tuesday 31 January 1978.
Helen came back to the rendezvous point five minutes earlier than Rita at 9.25pm. The opportunity to make an extra £5 before her sister returned was too good to miss, so Helen got into the car with Peter Sutcliffe. They drove to Garrards timber yard near the railway, a common haunt of prostitutes and their clients. Peter convinced her to get into the back seat, as she did so, Peter struck her with the hammer. He missed and hit the car door instead, alerting Helen to the danger she was in, but before she had a chance to scream he had hit her again. She immediately crumpled to the ground. It was then that Peter realised they were in full view of two taxi drivers who stood talking nearby. Taking Helen by the hair, he dragged her to the back of the woodyard. Still alive, Helen vainly attempted to protect herself from the hammer as Peter crashed it down onto her head again.
Scared that the taxi drivers would discover them, Peter lay on top of Helen and covered her mouth with his hand, then had sex with her as she lay bleeding. Finally, the taxi drivers left and Peter got up to find his hammer, which he had dropped. While he searched, Helen attempted to escape. As she ran from him, Peter hit her several more times on the back of her head. Still alive, Helen was dragged to the front of the car where Peter stabbed her through the heart and lungs with a kitchen knife he had hidden in his car.
Rita arrived back at the rendezvous point only five minutes after Helen had driven to her death. After waiting for some time in the freezing cold, she gave up and went home, assuming that Helen would be waiting for her there. Fear of the police prevented her from reporting Helens disappearance until Thursday. On Friday 3 February, a police Alsatian dog located Helens body where by Peter Sutcliffe had left her on the previous Tuesday.
On 10 March 1978, George Oldfield received another letter in which the writer claimed to be the Yorkshire Ripper, again it was post marked as being sent from Sunderland. The murder of Joan Harrison was again mentioned and he promised that the next victim would be old. Uncertainty about the validity of the letter increased when the body of Yvonne Pearson was found on 26 March 1978. If the letter had been from the murderer, why did he not mention Yvonnes murder, which had occurred two months earlier? A fact that only the murderer could have known, unless of course, the Ripper had not really killed Yvonne.
She had been found on wasteland off Lumb Lane in Bradford by a passer-by who had noticed her arm sticking out from under an old sofa that had been dumped there long ago. The fact that she had been bludgeoned with a large blunt instrument, presumed to have been a rock, caused police to wonder. This was not the Rippers usual method, but many of the other characteristics of this murder were similar to the other deaths.
Yvonne Pearson, had left her two girls, aged two years and five months, in the care of a babysitter on the night of 21 January 1978, to see if she could earn some money. Her first stop that night had been the Flying Dutchman Pub, which she was seen leaving at 9:30 pm. Soon after that, Peter Sutcliffe invited her to get into his car to do "some business." At the murder site, he hit her repeatedly on the head with a lump hammer. When she was dead, he hid her body under the sofa and jumped on her chest until her ribs had broken. Fear of discovery by people in the area had cut short his time with Yvonne and he had not stabbed her. A newspaper, dated one month after her death, was placed under her body leading police to believe that the killer had returned to the scene of the crime.