At first glance, Detlef M., in his brown leisure jacket, looks as if he were just dropping by room 011 of the Bonn Regional Court, a pensioner who is passing the time by attending trials.
But the 66-year-old man is accompanied by a judicial officer – and he is handcuffed.
Detlef M. has already spent more than half of his life behind bars because of a brutal double murder as well as property and drug crimes.
Now the public prosecutor wants to prove that he is also the murderer of Claudia Otto from Lohmar near Bonn.
Political correspondent in North Rhine-Westphalia.
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The then 23-year-old Claudia was tied up with nylon stockings on May 9, 1987 in her parents' country hotel "Naafshäuschen" and then strangled with a tie.
Then the murderer ransacked the young woman's apartment above the restaurant and stole the daily earnings from the local safe - around 6,100 marks.
"My client would like to explain that he did not commit the accused act," M. said his defense attorney at the start of the trial two weeks ago.
Detlef M. himself is adamantly silent, following the main hearing attentively and without any outward signs of nervousness.
One of the currently most exciting cold case procedures
Defense attorney Uwe Krechel made an even more agitated impression on Thursday morning.
"Today is the day of days," trumpeted the lawyer.
Prior to that, in a long, fundamental appeal to the chamber about doubts, illegitimate considerations of plausibility, science, God and the world, he made it clear that he believed little or nothing about the prosecution's arguments.
The case of Claudia Otto is currently one of the most exciting cold case proceedings, i.e. a procedure that has so far remained unsuccessful despite intensive efforts, sometimes spanning decades.
This second day of the trial is all the more crucial.
The chamber hears three experts on the central question of whether a DNA sample evaluated according to the latest technical possibilities is sufficient to convict Detlef M. as a murderer after 35 years.
It is the fourth attempt that investigators have made against the man.
Shortly after the murder, the former concrete worker was targeted by the police and public prosecutors because he was heavily in debt due to his lavish lifestyle and gambling addiction and was a regular guest at the "Naafshäuschen".
M. had already spent several years in prison for various drug and property offenses and was known to the police as a ruthless criminal.
Ironically, in his son's bed he had hidden heroin worth 140,000 marks and 3.2 kilograms of hashish.
Murder of 15 month old Patrick
But in 1987, in the case of Claudia Otto, M. could not be proven with the available criminalistic means, at that time fiber traces were the focus of the investigations, the systematic analysis of DNA traces was not yet to be thought of at that time.
Dozens of fiber traces were also taken from Claudia Otto's body using adhesive foil.
None led to Detlef M. According to the prosecution, these slides are now the decisive piece of evidence.
A few months after the landlord's daughter died, M., who was unemployed at the time, moved to the Sauerland with his wife and children.
Where the 180,000 marks for the house they bought there came from remained unclear.
A short time later, on November 12, 1988, M. broke into the remote villa of the Padberg entrepreneurial family in Eslohe.
He wanted to kidnap 15-month-old Patrick to extort a ransom of 1.2 million marks.
But the project got out of hand when the grandmother managed to grab the child's arms and legs.
M. strangled the woman.
Patrick didn't live long either.
"He just couldn't be tamed, he kept screaming in the car," M. later reported.
"I just wanted him to finally be quiet." M. buried the body in a wooded area – and then made multiple phone calls to demand ransom from the parents who had rushed back from a short vacation.
Phonetics experts at the Federal Criminal Police Office were soon certain: the caller was born in the Rhineland and was 30, at most 40 years old.
The Dortmund investigators responsible had just begun to scour the Sauerland residents' registration offices for people who had moved in with this characteristic when their colleagues in Bonn received a reference to Detlef M. and files on the Claudia Otto case, among other things.