The British government has so far declined to reveal why Venables had been recalled into custody.
Legal commentator Alan Caplin told CNN police would not have acted lightly given the amount of money the authorities have spent on giving the boys new homes and identities.
"I think one can surmise reasonably that... it must be quite serious if there's some intervention in that reset life," he said.
The conditions imposed on the boys on their release banned them from contacting each other, Bulger's family or from returning to the region of Merseyside, in northwest England, where the crime was committed .
British Home Secretary Alan Johnson told Sky News the reason for the recall would be revealed in time.
"I believe the public do have a right to know and I believe they will know all the facts in due course," he said.
However, British Justice Secretary Jack Straw was quoted in the Times Wednesday as saying it was in the public interest to withhold the details.
"I have no interest in gratuitously or unnecessarily withholding information, but there are good reasons to withhold it at the moment and that is in the public interest," he said.