Detectives investigating the murder of 11-year-old Rhys Jones believe his killer could be as young as 13.
Rhys was walking home after playing football when he was shot by a youth on a black BMX bicycle at a pub car park in Croxteth, Liverpool.
The youth is said to be white, aged 13 to 15, about 5ft 8in tall and wearing dark clothes and white trainers.
Rhys's mother Melanie cradled her son as paramedics battled for 90 minutes to save his life.
Two local boys, aged 14 and 18, who were arrested on suspicion of murder were released on Thursday night.
Merseyside Police are continuing to appeal for the community's help in catching the killer.
Officers have been handing out leaflets in the area with a special number for young people to text information anonymously.
Assistant Chief Constable Simon Byrne told the BBC: "Young people text each other frequently and we want information about who the killer is.
"We believe the killer is aged between 13 and 15 years of age and it is about making it easier for people to tell us if they have seen something, do they know the identity of the killer and where he is hiding now?"
Speaking at a news conference on Thursday, Rhys's mother said: "Our son was only 11, our baby.
"This should not happen, this should not be going on. Please help us."
Rhys's father Stephen said: "We have lost our world, the world has lost a good guy.
"He was football-mad, absolutely football-mad, a season ticket holder with me and his brother.
"Football was his life. If he wasn't watching it, he was playing it."
Rhys's favourite team Everton have confirmed there is to be a minute's silence in his memory before Saturday's home game against Blackburn Rovers.
The club has also sent a message of condolence to his family, while captain Phil Neville has joined calls for members of the community to come forward with information.
Rhys's mother was not aware of any guns on the estate.
"He had a thing in school about guns, the police went in. He was very aware of that, he was a very bright and sensible lad," she said.
Rhys's football coach was the first to contact Mrs Jones over the shooting.
She was then driven to the scene and found her son lying on his back unconscious.
She said she held him in her arms, but could not speak to him.
"He didn't come round. He was lying there in a pool of blood," she said.
"They tried for an hour and a half to resuscitate him, but his little body couldn't take it.
"Our whole family is devastated."
'Little laughing boy'
Relatives, friends and neighbours gathered at a vigil for Rhys at Emmaus Church of England and Catholic School Primary School in Croxteth on Thursday evening.
It is yards away from where Rhys was shot on his way home from football training.
Tony Edge, who broke the news of the shooting to the family has also appealed for people to come forward.
He said: "Tell the police, they don't have to give their names or anything, they just have to give this person up.
"This is a little kid who went to play football, who doesn't do any harm to anyone.
"I had an image of Rhys, this little laughing boy, and my final image of him isn't that, my final image of him is him lying there in a pool of blood."
Anyone with information can text the word "crime" followed by their message to 61051.