When Andreas T. entered the Internet café at Holländische Strasse 82 in the central German city of Kassel, Halit Yozgat had less than a quarter of an hour to live. As usual, the intelligence officer hesitated at the door. He checked whether any of his colleagues were nearby.

T. worked for the Kassel office of the Hesse branch of the Office for the Protection of the Constitution, Germany's domestic intelligence agency. He didn't want to be seen when he tried to make contact with women online.

The coast was clear on April 6, 2006. Only four customers and a child were in the store. Behind the desk sat Halit Yozgat, who worked in his father's business. Yozgat was on the phone. With the receiver held to his ear, he pointed the agent to the computer at station #2. At 4:50 p.m. and 56 seconds, Andreas T. logged on to the iLove.de dating site under the user name "wildman70".

The minutes and seconds that followed this moment have now become the focus of a number of parliamentary investigative committees, numerous public prosecutors and a host of investigators throughout Germany. Shortly after the local intelligence official -- code name: Alexander Thomsen -- started to flirt online on that fateful Thursday in Kassel, Halit Yozgat died only a few meters away. He was killed with two shots to the head fired from the same Ceska 83 pistol that members of the National Socialist Underground (NSU)  used to kill a total of nine men of Turkish and Greek origin before their terrorist cell was finally exposed in November 2011.

Since then, Germany has had to live with the realization that its well-equipped security apparatus was incapable of even recognizing the existence  of such a murderous group for nearly 14 years. The revelation that an intelligence official involved in the fight against right-wing extremism was on the scene of one of these murders sparked a torrent of conspiracy theories.

'Incredible'

Germany's mass-circulation Bild newspaper wrote of a "suspicion" that was "so incredible, so unfathomable!" and claimed: "The agent was near the scene of the crime in six of the nine murders." Even the weekly newspaper Die Zeit, which has a reputation for quality journalism, asked: "Did an officer with the Hesse Office for the Protection of the Constitution commit one of the NSU murders?"

Today, after months of inquiries, investigators have ruled out the possibility that intelligence officer T. was involved in the NSU murder in Kassel. There is also no evidence that he was at any of the other murder scenes. But investigative reports indicate that the actual scandal has to do with how the Hesse branch of the Office for the Protection of the Constitution dealt with the case: The intelligence agency obstructed the investigations of the homicide division.

The case is now putting pressure on the Hesse state governor, Volker Bouffier of Chancellor Angela Merkel's conservative Christian Democratic Union (CDU). Bouffier, who was state interior minister at the time, helped to thwart the criminal investigators. He gave orders that made sure that the homicide squad, codenamed "Café," would not be able to freely investigate within the milieu of his state domestic intelligence agency. With Bouffier's support, access to witnesses was restricted.

Was his intelligence agency's interest in protecting its own sources more important than clearing up a murder series? This month, the former state interior minister and the then director of the Hesse intelligence agency will have to explain their actions to the NSU Investigative Committee of the German parliament, the Bundestag, in Berlin.

Online for 10 Minutes and 44 Seconds

The Yozgat murder case struck the "Café" investigators as odd right from the start. At the scene of the crime, they noticed inconsistencies as they tried to locate possible witnesses. Four witnesses who were at the Internet café at the time of the murder were quickly located. The fifth customer, however, didn't come forward, even after investigators made a public appeal.

Police worked feverishly to identify the unknown man. They checked the computer at station 2 and established that the user had been online for 10 minutes and 44 seconds. From his seat, he would have been able to see through the open doors and view part of the entrance area.

In the same room, according to the police reconstruction, witnesses 1 and 2 -- two boys, aged 14 and 16 -- were surfing porn websites. They wondered why the man at station 2 only surfed the Internet briefly, although he would have had half an hour's time for 50 cents.

Witness number 3 -- a pregnant woman who had come into the café with her three-year-old daughter -- was talking on the phone with her brother in Turkey. Up until the murder, it had been a normal afternoon for her.

'Like a Balloon Popping'

At 4:54 p.m., roughly 5 minutes before the deadly shots were fired, witness number 4, Faiz H., picked up the receiver in booth 3. The phone booth was located only a few meters from Yozgat's desk. The Iraqi talked on the phone with his back to the glass door. Shortly before he hung up at 5:01 p.m. and 2 seconds, he heard a bang followed by another. He later described the noises as sounding "like a balloon popping."

At this moment, Yozgat slumped to the floor, fatally wounded.

A poster on the phone booth's glass door blocked the Iraqi witness's view of the crime scene. Shortly thereafter, he says that he saw through a slit a "muscular man, roughly 180 cm tall (nearly 6 foot), wearing light-colored clothing," who glanced at the desk and was in a hurry.

If the Iraqi's statement is true, then the unknown man must have still been logged onto his computer at the time of the killing. Did he see the murder? Did he leave the Internet café out of fear of being discovered at the scene of the crime?

A few minutes later, the victim's father, Ismail Yozgat, entered the store. "My son! My son!" he shouted when he discovered Halit behind the desk.

The Fifth Man

It took nearly two weeks for police to discover the mysterious fifth man. Investigators tracked him down thanks to his online communication on the iLove dating site. Although the unknown man always logged on under the pseudonym "wildman70," he had provided his real cell phone number, which led investigators to Andreas T., the intelligence agency operative.

The agent at first denied even having been at the scene of the crime at the time in question. He claimed that he had been at the Internet café one day before the murder. Finally, he had to correct his earlier statement, but still maintained that he had left the premises before the shots were fired.

Investigators were incredulous: If T.'s version of events were correct, the killers would have had a maximum of 41 seconds to carry out the crime. Police specialists concluded that this was possible, but extremely unlikely.

For the homicide division, the man from the domestic intelligence agency was now their main suspect. They researched his past and discovered that he had pursued a low-key but steady career with the Hesse Office for the Protection of the Constitution.

'Extremely Motivated'

Andreas T., who is 45 today, worked his way up through the ranks. After leaving school, he joined the German military, the Bundeswehr, then became a postal clerk, and finally landed a job with the Office for the Protection of the Constitution, where he started out as an observer in Offenbach near Frankfurt in 1994. In 1998, he became an investigator at the Kassel branch of the organization, then gradually managed to improve his position until he was promoted to chief inspector.

T. is described as a withdrawn person who is "extremely motivated and ambitious," in the words of one of his colleagues. He was a bit of a loner who maintained a secondary residence at his parents' place and had few friends.

When his relationship fell apart in early 2000, T. realized that he had "hardly any social contacts," as he admitted. In an effort to change something in his life, he joined the Hegelsberg Gun Club. He didn't tell his parents or, later, even his wife about his hobby.

When his apartment was searched after the murder, police found a Smith & Wesson .22 caliber revolver, a Heckler & Koch .45 caliber pistol, a Beretta 9 mm and a Fabrica de Armas rifle, plus shotgun cartridges and blank ammunition, a baseball bat, brass knuckles and a knife. T. had a license for the guns, but not for some of the ammunition.

A Forged Hitler Signature in the Attic

In the attic of his parents' apartment, investigators came across excerpts from "Mein Kampf," which T. had typed with an old typewriter and embellished with seals from the Third Reich and a forged signature of Adolf Hitler. They also found a handwritten copy of all three verses of the German national anthem (including the first verse which is no longer sung because of its Nazi associations) and a copy of the book "Immer wieder töten" ("Killing Again and Again"), a compendium of police investigations into serial killers.

T. told investigators that he wasn't a right-winger, but that he had toyed with the idea for a while as a young man. Had he fallen in with the wrong crowd, T. admitted, he might have ended up "sympathizing with the right-wing spectrum." It would be closer to the truth to say that he openly endorsed right-wing extremist ideology at the time; he was nicknamed "Little Adolf" in his neighborhood. During the raid, police also found 3.7 grams (0.13 ounces) of hashish. The drug, explained T., was from his old army days in the early 1990s. He said he had kept the hash in a little leather key bag, placed it in his safe, and then forgotten about it over the years.

So this was T., the official who was supposed to protect the Germans and defend democracy. The fact that someone with such a personality and such a past could end up working for an important intelligence agency is problematic enough. But investigators were more interested in the evidence that had come to light: a gun freak and a loner, a former right-winger and a drug user. Was T. the murderer?

When they questioned him about his penchant for visiting dating sites on the Internet, T. spoke of "escapes" from everyday life -- escapes like the one that led him to the Internet café in Kassel on April 6, 2006. The police went to great lengths to find out what the operative did on that day. He was wearing, as the homicide detectives discovered, a pink shirt without a tie, and a black coat. Investigators also soon knew all the details about his work day: where he drove, whom he met, when he clocked off work -- at exactly 4:43 p.m. that afternoon.