A police officer and scout leader who sexually abused boys as young as eight has been jailed for 22 years.
Allan Richards, 54, who served with West Midlands Police for 31 years, was convicted of 40 offences against boys and young men.
He kept a list of boys he was attracted to and used a police database to access information about young men.
The Independent Police Complaints Commission is investigating the force’s handling of the case.
Richards was questioned after concerns were raised but he was able to carry on working.
Sentencing, Judge Francis Laird QC told Richards “It’s abundantly clear to me you have been a sexual predator all your adult life.”
He added: “I observed you, Mr Richards, over the course of many weeks and you have shown no remorse for what you did or for the damage that you have done to so many individuals.”
The court earlier heard 17 people were assaulted between 1976 and 2013.
Attacks took place at locations including a police station, scout camps and swimming pools.
Richards, of Tile Cross in Birmingham, was questioned after concerns about him were raised in both 2000 and 2004.
He was banned from contact with the public but avoided criminal proceedings because West Midlands Police said it was advised it was unlikely to achieve a successful prosecution.
IPCC Commissioner Derrick Campbell said it was “deeply disturbing” Richards abused his position of trust and authority over many years.
“Richards’ victims will not be alone in wanting to know if West Midlands Police could have done more between 2000 and 2008 to bring him to justice,” he said.
“Our independent investigation will examine whether more could have been done by the force to uncover his activities sooner and if there are any lessons that can be learned from this.”
All copyrights for this article are reserved to bbc uk