The crime took place on February 18th when a man attacked a 33-year-old woman in a park.

According to a secret police report seen by the Rheinische Post (RP) and the Westdeutsche Allgemeine, the man put a hood over the woman’s head before strangling her and forcing her to the ground. He then ordered her to take off all her clothes before raping her several times.

Police were able to arrest a 30-year-old suspect once they had questioned the victim. But instead of writing a press release about the crime, as is normal police practice, the Bochum police headquarters sent a confidential report to the North Rhine-Westphalia interior ministry.

Questions are now being asked as to why the police kept the crime secret. The RP writes that one possible reason is that the suspect is a convicted sexual offender, who was supposed to still be under observation.

The 30-year-old, convicted of sexual assault for crimes that took place in 2009 and 2010, was considered a potential risk to the public and had been listed for surveillance under the so-called Kurs programme.

The decision to keep the case secret provoked anger within the police force, with one officer telling the RP that “the public has the right to know that convicted sex offenders pose a real risk when they are released from prison.”

“If we hide this information then the public will get the impression that everything is fine and that people in the Kurs programme don’t reoffend,” he added.

The police in North Rhine-Westphalia have come in for criticism several times over recent years due to their perceived failure to adequately respond to serious crimes.

Failings in the observation of radical Islamist Anis Amri meant that he could leave the western state for Berlin without being adequately tracked. He went on to commit a terror attack in which twelve people lost their lives at the end of 2016.

Police in Cologne, meanwhile, did not immediately inform the public of a series of sexual assaults that took place during New Year celebrations at the end of 2015. On that occasion too, they were accused of hiding information due to the sensitivity of the crimes – descriptions of the attackers suggested many of them came from North Africa.