Melisa M., 20, a witness in the trial of a neo-Nazi gang accused of a crime spree and the murder of Turks, was found dead in her Karlsruhe home on Sunday. The young woman was the ex-girlfriend of a witness with ties to the National Socialist Underground (NSU), who died under mysterious circumstances two years ago. Her death sparked suspicions over a possible cover-up in the case, especially after media reports and statements by victims' lawyers pointed to the involvement of German intelligence with the gang. The local prosecutor's office announced she died of a pulmonary embolism or a blood clot in the lung, according to initial autopsy results. The victim was slightly injured in a motorcycle accident last week and doctors had operated on Melisa M. twice to prevent thrombosis following the accident. Melisa M. had testified earlier this month to a special committee in the state of Baden-Württemberg where the NSU is accused of killing a policewoman five years ago. The hearing where she testified was closed to the public as she said she felt "threatened," according to the German media. The committee's head Wolfgang Drexler told German media they would wait for the final autopsy results before commenting on the death. The victim's ex-boyfriend Florian H. was found burned to death in his car in Stuttgart two years ago. A former neo-Nazi, he reportedly had connections with the NSU and German media outlets claimed he knew who murdered Michele Kiesewetter, the slain policewoman. His death was treated as suspicious as it happened before he was to testify to police on the case, though an investigation could not find any foul play. Prosecutors recently reopened the case on his death after his family found guns and a set of keys that may provide evidence regarding his death. It is not known how the police officers who investigated the scene did not see the gun. Melisa M. is the third witness to die since the trial began. In 2014, Thomas R., another witness, died of a previously unknown diabetes disease. Thomas R. was reportedly an informant for German intelligence.The NSU, which is composed of two men and a woman, is accused of killing 10 people including eight German citizens of Turkish origin, a Greek man and a policewoman, carrying out bomb attacks and bank robberies between 2000 and 2007. Beate Zschaepe stands trial as the only surviving gang member while four others are tried on charges of aiding and abetting the gang members. The trial, which started in 2013, is marked by postponements over technical issues and the silence of Zschaepe in the courtroom throughout hearings. After the discovery of the NSU, it was revealed in the trial that the gang had connections to informants recruited by the German intelligence service, which raised the question of whether the intelligence officials had knowledge of the gang's activities and deliberately ignored it.Lawyers for the Turkish victims of attacks had complained earlier that the German state failed to shed light on the gang's "connections" to German intelligence services.In a hearing in January, lawyers for Ralf Wohlleben, a suspect accused of aiding and abetting the gang to a hideout, requested the court summon a group of people with neo-Nazi connections to testify in the case over allegations that other far-right groups helped the NSU. Lawyers had claimed Blood and Honor, an illegal neo-Nazi organization, may be behind the gang as it promoted a system with independent, armed cells in pursuit of the neo-Nazi cause. They claimed a group of neo-Nazi fanatics operating in secret sustained the gang by funding and arming it.