The Yorkshire Ripper Peter Sutcliffe is believed to have been taken to Sunderland Royal Hospital.
Peter Sutcliffe, 72, an inmate at HMP Frankland, Durham City, was reportedly taken to Sunderland Royal Hospital late on Sunday evening.
Patients are believed to have seen the serial killer surrounded by guards on one of the wards at the hospital. It is not known if Sutcliffe is still at the hospital, in Kayll Road, Sunderland.
One person who spotted Sutcliffe at the hospital said he had two guards and two police officers with him on Sunday evening.
They said he looked different and now had grey hair and look bloated. Sutcliffe also had chains around his wrists and ankles.
The former lorry driver, who was arrested in Sheffield 1981, is currently serving 20 life terms for murdering 13 women and attempting to kill seven more.
Sutcliffe was registered blind but is believed to have undergone laser eye surgery to save his sight at Sunderland Eye Infirmary last year.
Sutcliffe, who uses the name Peter Coonan, attacked his victims, most of whom were prostitutes who were mutilated and beaten to death, between 1975 and 1981.
He was diagnosed with paranoid schizophrenia following his life sentence but was moved to Frankland Prison in Durham from Broadmoor psychiatric hospital last year after a ruling that he was sane enough to be transferred.