A senior police officer defended the actions of his officers after it was revealed the two brothers were involved in an attack on another 11-year-old youngster just days earlier.
This victim, who also cannot be named, was injured when he was lured to an isolated spot and attacked by the boys in Edlington a week before.
The pair were due to be interviewed about this incident on the day they seriously injured the other two boys but did not turn up at the police station.
They subsequently admitted assaulting the boy, causing him actual bodily harm.
Temporary Superintendent Ian Bint, of South Yorkshire Police, said the brothers, who were 10 and 11 at the time, could not have been held in police custody in any case because of their age.
And he said it was reasonable for the officers to have arranged an interview three days after they were named as suspects, partly because it was a Saturday and they were not at school.
Mr Bint said police discovered the names of the brothers through the local school on April 1.
The boys were due to be interviewed on April 4 but ran away from their foster parents' house.
Mr Bint said: "The names of those boys came to us on April 1 and that was acted on and, bearing in mind the age of the children, we arranged to interview them within three days.
"With the inquiries that were done and the nature of that offence, I'm quite satisfied that those timescales were appropriate."
The officer added: "By April 4 we'd arranged to interview those children, bearing in mind we also have to video-interview the victim and there was also an outstanding witness who didn't come to light until several weeks later."
Mr Bint said: "It's important to remember what action can be actually be taken against children of this age and what the law is about. Children under 12 cannot be remanded in police custody. That is a matter of legislation.
"So both these children - the perpetrators - were both under the age of 12.
"So although we could have interviewed them - it could be argued we could have interviewed them a little bit earlier - but that would not have resulted in them being remanded in custody and there were still outstanding witnesses into that case."
Asked about what was done in response to the brothers failing to attend the police station on the Saturday, he said: "We got a phone call just before they were due to arrive to say they had run off.
"Now they did actually return back to their foster carers after a short period of time and we were informed of that, but once again ran off.
"The timescales we are talking about here are less than an hour - very, very short periods of time between them running off and the second attack."
Asked about reports that the earlier victim's mother told officers the names of the brothers but had been told to "stop bandying names around", Mr Bint repeated that his officers heard the names through the school on April 1.
The officer admitted that the brothers and their family were known to police when they were living in a different part of Doncaster for several years.
They moved to Edlington to live with foster parents only a few weeks before these incidents.
Mr Bint said the officers investigating the incident at the end of March were aware of the boys' history.
He said issues of inter-agency working in the years before the attack was a matter for the serious case review.
But he added: "You have to remember just how unusual this case is. These children were so young."Reuse content