Every year, around 2,000 complaints police brutality in Germany are reported – and the figure could be higher because not every case is reported. But one case is so brutal that it is unforgettable – it involves 23 year old Teresa Z. from Munich. In an image, her whole face is bruised, and her nose and eye socket are broken. She had called the police after a fight with her boyfriend got out of hand. But in the end, the worst blows didn't come from her partner but a police officer - out of self defense, he says. The investigation is ongoing.

"We will never be able to rid ourselves of this problem completely," Udo Behrendes, the head of police in Cologne told DW. Police officers often encounter violent situations - its part of their job. Mistakes can happen, Behrendes said, "but we can get more professional."

In 2002, Behrendes was put in charge of four Cologne police departments - one of which was in the notorious Eigelstein district, where police officers were so violent with a suspect that he later died of his injuries.

"We have taken our time. A year and a half, to completely turn this police station around," he said.

According to Behrendes, the end of this cleansing process brought about a different self-perception among the police officers and changed how they see their job - professionalism is no longer defined by being the stronger one, but by acting as a conflict manager. And team spirit is no longer about covering up the misconduct of colleagues.

In 2010, demonstrations against plans to renovate Stuttgart Central Station led to some violent altercations

Theory versus practice

This way of handling shortcomings is by far not representative of all police departments, according to Thomas Feltes, a researcher on policing at the Ruhr University in Bochum.

"We have a structural problem here. Dealing with mistakes that happen during police work, just like in any other job, has room for improvement," he said, adding that more than often, the reflex of police chiefs is to protect their officers - even before the case has been properly looked into. That's because most of the police officers in the higher positions got their training 20 to 30 years ago when the prevailing philosophy was the police do not make mistakes.

"To a certain extent we have the transitional problem of coming from a non-enlightened police leadership that is caught up in antiquated thought patterns, moving towards a new generation that approaches matters in differently," Feltes said.

Today, fundamental and human rights are an integral part of police training. This is excellent, said Amnesty International's Alexander Bosch. But there is a significant discrepancy between what's being taught in training and what happens in practice, he added.

"There are well-trained officers starting their duty, but whenever they happen to be posted to a police department that has a different climate, the officers often adapt," Bosch explained.

Sloppy investigations

Most of the time, police investigations are abandoned far too quickly, Bosch noted: "90 percent of the police officers are not convicted." Amnesty International has been documenting cases of unlawful police behavior for years. The organization looked into the history of several cases, Bosch said, "and what we found was that police officers don't investigate as diligently against fellow officers as against regular citizens. And what's more is that the prosecution nods off this practice as well."

Police tend to be less diligent when investigating against fellow officers, says Amnesty International

Alexander Bosch is advocating for an independent investigative commission - it has been the long-standing practice in other countries like the UK. But German policy makers are yet to warm up to the idea, in spite of rebukes from the EU and the UN. Nevertheless, the level of police violence in Germany is rather low when compared to other countries.

More prevention, less reaction

And experiences, like those of Udo Behrendes, show that Germany can still improve.

"We didn't find that one switch which needs to be turned. Rather we implemented a whole number of rather unspectacular measures," he said. Apart from intensive discussions about the self-perception of the police officers, there was also hands-on trainings.

Under Behrendes' leadership, his staff thoroughly informed themselves about difficult groups that they had to deal with in their work - drug users, prostitutes, biker gangs. The goal was to understand them better so that they could react quickly when needed. It has been 10 years since Udo Behrendes began to address police violence in Cologne's police force.

"It's my impression that we have gotten a lot more relaxed about it," he said. "We've gotten better at dealing with the violence we encounter, and better at controlling ourselves."