Blake Ross, 13, was discovered on a Lothian Bus on Monday after he was reported missing without his medication just a few days earlier.
The youngster, who lived at the St Katharine’s care unit in Howdenhall, passed away later in hospital after suffering a cardiac arrest.
According to the charity Who Cares?, Blake is now the third young person from a care background in Scotland who has passed away since the beginning of the year.
The charity, which supports children who have been through the care system, said it had knowledge of all three cases, one of whom was among the two teenagers who died in Her Majesty’s Young Offenders’ Institute Polmont last month. The other was a young woman who took her own life over the festive period.
Duncan Dunlop, chief executive of Who Cares? Scotland, said one young person aged under 25 in care had passed away each month since last July.
He said: “That is just those known to our network. I woke up to new statistics outlining that care-experienced people are more likely to be dead by the age of 21.
“Then followed the news one of our 13-year-old members had died after being found unwell on a bus.
“It is the third time I have received a call like that this year. We are thinking about all of the care-experienced young people we know today who are no longer with us.”
Mr Dunlop added that while Blake’s death appeared to be an accident, questions needed to be asked about why he felt the need to run away, as well as why so many young people with experience of the care system feel a lack of belonging in society.
Tributes have flooded in since news emerged of Blake’s death, with a JustGiving page set up to raise funds for his funeral bringing in almost £2000 in less than a day.
The page was set up by some of the teenager’s relatives, who stated they wanted to give Blake “the send off he deserves”.
One message on the crowdfunding website read: “He was a much-loved son, brother/triplet, grandson, nephew and great friend to many.
“Blake was such a lovely little boy and I feel us, the community, should do our bit to help give him the send-off he deserves, no matter how big or how small.
“Every little helps. RIP angel xx.”
The Police Investigations and Review Commission (PIRC) watchdog has now been called in to investigate officers’ actions relating to Blake’s death, with the city council also set to carry out a review of his care.
His death is being treated as unexplained by Police Scotland, with the organisation saying it would be looking into the circumstances in the 48-hours which led up to it.
Police superintendent Lesley Clark, previously said: “Our inquiries are ongoing and we would ask anyone with information regarding Blake’s movements between the afternoon of Saturday, February 11 and Monday, February 13 to contact us on 101.”