A man has been arrested on suspicion of murdering nine-year-old Lillia Valutyte in Lincolnshire.
Police said the 22-year-old suspect was held in the "Boston Central Park area" at about 2.45pm on Saturday and is now in custody.
Progress on the investigation into Lillia's death was made through a "combination of intelligence and information supplied by several members of the public".
"We are not looking for anyone else in connection with this incident," officers added.
However, Lincolnshire Police said its investigation remains in progress and there will "continue to be a significant police presence in the town".
Officers are still encouraging "anyone with information to contact us".
"We are in a very sensitive stage of our investigation," said Chief Superintendent Martyn Parker.
Earlier, the force released four CCTV images of a suspect taken five minutes before Lillia was found and warned people not to approach him and call 999 immediately if they spotted him.
The images were taken in the Wormgate and Fountain Lane area at around 6.15pm on Thursday, police said.
Lillia, who was fatally stabbed, was found on Fountain Lane at about 6.20pm on Thursday.
She had reportedly been playing with her younger sister on the street just yards from an office where their mother was working at the time.
The girls had a hula hoop, and a toy pram was left at the scene, according to local residents.
Marko Iosif, nine, was in the same class as Lillia and said she was "always really enthusiastic and always happy".
He will remember his friend as "always taking care of others", he told Sky News.
Marko's father, Alin, said Lillia's death was "terrifying" and "everyone is very scared".
He added that people "do not feel safe anymore" and parents are "scared to leave the kids in the street now".
Jurate Matulioniene, a family friend and chairwoman of the Boston Lithuanian Community, said Lillia loved dancing.
She told The Times: "Lillia was a beautiful angel, she was quite quiet and loved dancing.
"The family used to come to all of our community events and they would always stay late to help clear up.
"I have spoken to the mum and asked for her account details because we want to do a fundraiser but she would not accept it."