There are seven people currently recorded as missing by South Yorkshire Police
Sarah Walker was reported missing after last being seen on Glossop Road in the city on Thursday night.
Enquiries then established that the 32-year-old was later seen on a white mountain bike near a pharmacy in the Shoreham Street area of Highfield at 9.10am on Friday.
But she has not been seen or heard from since.
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Jaiyan Schmidt, aged 17, who has links to Aughton, Beighton and Woodhouse, Sheffield, was reported missing after last being seen close to Ponds Forge in Sheffield city centre on Wednesday, August 19. He has since been spotted in Sussex, where the search is now focused.
There are six other people currently recorded as missing by South Yorkshire Police.
Anyone with information should call the force on 101.
Christopher O’Hara, 29 and from Maltby, Rotherham, was last seen outside Meadowhall train station on July 22.
He has a griffin tattooed behind his right ear and ‘Kiaron’ on his right arm. Christopher is thought to be wearing an ‘excel logistics’ uniform which is black and red. Have you seen Christopher? Do you know where he might be? If you have information that may help, please call 101 quoting incident number 503 of 22 July.
Sarah Walker, aged 32, has not been seen or heard from since 9.10am on Friday, when she was spotted on a bike in the Shoreham Street area of the city. Concerns for her welfare are growing.
Malcolm James Bagley, 33, from Doncaster, has not been seen since he boarded an East Midlands train from Sheffield to St Pancras, London, at 2.29pm on Friday, June 12.
He has a tattoo of a cat wearing a top hat on this right arm.
Richard Dyson, 57, disappeared from his home in Barnsley on Friday, November 15, last year.
He dropped his daughter off at her home in Aston, Rotherham, and vanished.
Anthony Richmond, 62, has not been seen since he was captured on CCTV on Greenland Road, Darnall, Sheffield, at 8.52pm on Monday, November 11, last year. Anthony, who is from West Yorkshire, had been working in Sheffield. He is known to always wear a flat cap.
Andrew Gosden was 14 when he went missing from his Doncaster home in 2007. He was last seen boarding a train to London. Andrew, who is deaf in his left ear, has an unusual and distinctive right ear.