A two-year-old boy found face down in a canal had run off from his mother shortly before, police said today.
The youngster is fighting for his life following the incident in Burnley, Lancashire, yesterday afternoon.
Police are trying to piece together how the boy came to be in the water in the Leeds and Liverpool Canal in the town's Pit Top Park.
He was walking with his mother from the Colne Road area to another address when he ran off along Pheasantford Green some time after 5.05pm.
Police were alerted shortly after 5.30pm and an immediate search of the area was launched.
The Asian toddler was found by a police community support officer at 5.50pm.
He was taken by air ambulance to the Royal Blackburn Hospital and later transferred to Manchester Children's Hospital where he is said to be "very poorly".
Police want to hear from anyone who saw the boy or his mother in the area between 5pm and 5.50pm.
The boy is described as having short dark hair and was wearing a grey T-shirt, black trousers and white shoes.
His mother, who is also Asian, is aged 25, of medium build with long dark hair and was wearing dark coloured traditional Asian clothing and a head scarf.
Detective Inspector Marie Haworth said: "This is a tragic incident and we're working hard to piece together exactly how this toddler has come to be in the water.
"Monday was a nice sunny day and between 5pm and 5.50pm I am confident there would have been many people in the area travelling home from work, feeding the ducks or walking their dogs.
"We are appealing for witnesses in the area at the time who may have seen the little boy on his own or with his mum.
"At this stage we are keeping an open mind about how this little boy has ended up in the canal and that is why I am appealing to anyone who has seen him to contact the police.
"It is obviously an extremely difficult time for the family and we have specially trained officers there to support them."Suggest a correction