Isabelle Rose Welsh was found lying dead at the foot of the stairs at the home she shared with mum Alexandra Walker, 25, in Thornaby, Teesside, last September. Prosecutor Richard Wright KC said Isabelle had been a happy, healthy child until her mother started dating Harrison Simpson, 22, last summer. He was also convicted of sexually assaulting Isabelle while her mother was cleared of that charge. Harrison Simpson sexually abused the toddler before murdering her (Picture: NCJ Media)Walker’s concerned mother said it ‘looks like she is being abused’ during one visit after Isabelle’s leg was broken. The next morning Simpson got up – claiming to be looking after Isabelle – while Walker stayed in bed.