Mike Berry, a criminal psychologist, said the killer was an exceptionally cold-blooded and skilful operator.
"The killer may be confident he will not be caught," he wrote in the Daily Mirror. "He will be fascinated by the coverage of the case ... he will be thinking 'the game is on'."
A huge police inquiry began on December 2 when the body of Gemma Adams, 25, was found in a stream near Ipswich. Police found 19-year-old Tania Nicol's body in the same stream on December 8.