The search for the missing 13-year-old Yorkshire schoolgirl Erika Kacicova entered its sixth day, as police bailed the man they had been questioning over her disappearance.
The teenager was last seen at around 4pm on Monday when she left her home in Darnall, Sheffield.
A 22-year-old man from Bradford was bailed by police after being questioned on suspicion of child abduction by detectives in Sheffield.
Officers were carrying out door-to-door inquiries in Darnall, while a team from South Yorkshire Police were conducting searches in Bradford.
Police declared her disappearance a "critical incident". They believe Erika is with people she knows and are concentrating their search on the south abd west of Yorkshire.
They appealed directly to the missing teenager to get in touch, saying she was not in any trouble and that they would come to pick her up.
They urged anyone who was with her to encourage Erika to come forward.
Det Insp Helen Tate, from South Yorkshire Police, said: "We are very concerned for the safety of this child."
She confirmed there had been no positive sightings or confirmed contact with the girl since she went missing.
Det Insp Tate added: "She is a young girl, away from home and our main aim is for her to return safe and well.
"We know Erika's family have friends and acquaintances in the Bradford area, so she may well have travelled to West Yorkshire."
Det Insp Tate renewed her appeal for the teenager to make contact, saying, "Please let us know you are okay."
She added: "You aren't in trouble. We just need to know you are safe."
Erika is described as 4ft 11in tall, Eastern European, of slim build, with long, straight, dark brown and brown eyes.
She was thought to have been wearing blue jeans, a pink polo shirt and silvery-grey jacket.