"He was a faithful person searching to find the truth and essence of life. He was a gentle, open-hearted, talkative friend of ours during our university years," the words of a friend of the promising engineer who allegedly took his own life last week.

A graduate student from the Electrical and Electronic Engineering Department of Hacettepe University spoke to Daily Sabah on the condition of anonymity after the tragic death of his friend, and said: "I do not know what kind of a person he was in his professional life, but one thing is for sure, his life was dedicated to finding the truth and good in accordance to his faith. He believed in it from the bottom of his heart."

Kerem Parıldar, a faithful and warm person according to his friends, allegedly committed suicide on Nov. 21 by jumping off a building 15 kilometers away from the Koru neighborhood of Ankara where he was living. Parıldar, a 32-year-old senior electronics engineer, was working on local defense systems at Military Electronic Industries (ASELSAN), established under the Turkish Armed Forces Foundation in 1975 to provide the Turkish Armed Forces (TSK) with communication devices. The reason why this young man with a satisfying salary, prestigious status and a bright future chose to cut his life short is unknown. More significantly, what makes this case even more noteworthy is that this is not the first but the eighth suspicious death in the company over the past 11 years.

When the details of the other suicides, each with a complexity all its own, are examined, the questions surrounding Parıldar's death seem to only increase.

This crime fiction-like series of events first started with Hüseyin Başbilen, a 31-year-old graduate of Middle East Technical University (ODTÜ), one of the most prestigious universities in Turkey. He invented the steel scopes for Kanas sniper weapons for shooting at night and had been working on ASELSAN's national tank project. He was found dead in his car with his throat and wrists slit on Aug. 4, 2006.

This alleged suicide happened just a day before he was supposed to make a presentation about his new project. The fact that his throat was cut before his wrists according to the autopsy reports raises suspicions about every aspect of his suicide, especially considering there were also claims that his hands and throat had signs of being bound. Footage of the gas station where Başbilen stopped before his death were not included in the 2006 investigative files, and the flash disk containing his project's documents is not listed in gendarme records, even though it was found at the crime scene investigation team.

However, those details of the case had remained in the shadows until recently when the prosecutor in charge of the Başbilen investigation, Murat Demir, was fired due to his alleged connections to the Gülenist Terror Group (FETÖ). The criminal police officer that examined the handwriting on Başbilen's suicide note is also suspected of having ties to the terrorist group. Further investigations found that doubts surrounding the case may have been legitimately based. In 2017, 11 years after the case opened, his father, Vehbi Başbilen, spoke to Sabah daily, and said: "They closed the case based on a so-called suicide letter. They said there was inaccuracy in the autopsy report. Even though he did not go to the hospital, they reported that he had stayed in the hospital for a while. My son did not commit suicide. He was murdered."

The deeper the investigation digs under the guidance of newly appointed prosecutor Hamza Yokuş, the stronger the evidence supporting the claims that Başbilen did not commit suicide but rather was a victim of murder, just like his six colleagues.

Demir, the previous prosecutor, was not the only person revealed to have alleged connections to FETÖ. Moreover, the investigation files of seven alleged suicides of other engineers, Hüseyin Başbilen, Halim Ünsem Ünal, Evrim Yançeken, Burhanettin Volkan, Zafer Oluk, Hakan Öksüz and Erdem Uğur, all contain unanswered questions and suspicious details just like Parıldar's recently reported case.

Retired Master Sgt. Mahmut Volkan, the father of the fourth victim, Burhanettin Volkan, wrote a letter to the prosecutor in charge of the "spying investigation," Fikret Seçen. According to what was published by Akit daily, he wrote: "My son seemed irresolute to me when he was at home. He thought he was being chased by snipers. He kept saying 'boom,' while pointing to his forehead with his finger like a gun. He once said that he should die instead of us." The grieving father further claimed in his letter to former prosecutor Şeçen, who is now a fugitive for alleged ties to FETÖ, that chemicals had affected his son and that after his death, all of his organs were taken for donation without his permission. Communication and software engineer Burhanettin Volkan had been working in the plane command and control center. He was found in a watch officer's room in a military school shot dead by a visor gun on Oct. 7, 2007.

Evrim Yançeken, an ODTÜ graduate engineer, was also working on military projects like Başbilen and Volkan. He reportedly committed suicide by jumping off the building where he lived, and just like Parıldar, had no known reason to commit suicide according to a statement his friend gave to Daily Sabah. Yançeken supposedly left a suicide note saying that he was having a hard time studying for his master's thesis. His neighbors provided statements indicating that he may have been having a hard time with his master's degree. The case was supported by testimonies and required no further investigation. His mother indicated that her son was very happy with the institution where he worked and that ASELSAN was the only place he wanted to work for, according to reports by Hürriyet daily. Why would a successful young man like Yançeken, who had a seemingly successful professional life, use it as a reason to commit suicide?

The reported suicide notes had something in common in almost all of the cases. Halim Ünsem Ünal, a 30-year-old engineer, graduated from ODTU just like his colleagues. He was found dead with a bullet in his head in his car near Gölbaşı, a district in Ankara, on Jan. 17, 2007, just a few days before his wedding. Similar to Başbilen, he was supposed to attend a seminar on the defense industry. The case was listed as a suicide. Ünal, a successful engineer, graduated from university with honors in 2000 and was working on F-16 fighter aircraft.

Hakan Öksüz was almost considered lucky when he was rescued by a passerby after his throat was slit in 2007. The case was shocking. He was not allowed to work on projects due to psychological issues for a while. On Jan. 25, 2012, he was involved in a traffic accident on Eskişehir highway, a year after he had sent his family to his hometown due to concerns about their safety, according to Sabah daily. Öksüz was working on a microelectronics guidance and electro-optics project.

Zafer Oluk, a promising young man, graduated from ODTÜ's electrical and electronic engineering department and was on a team working on the development of Leopard tank software systems. He died as a result of an electric shock on May 10, 2008, in the military unit where he was serving as a soldier. His father questioned the situation in the statements he gave to Takvim daily at that time, saying: "My son was an intelligent electronics engineer. Why would he be so careless around a malfunctioning transformer?" The questions remained unanswered, case closed.

Erdem Uğur was the most recent victim until a few days ago. He was found dead in his house in Ankara on Jan. 16, 2015. His death was recorded as suicide by gas poisoning. Uğur, an expert in the field of magnetics, was working on F-16 fighter aircraft, unmanned combat air vehicles, tanks and combat weapons.

Over the past 11 years, eight promising, successful engineers working for the same company supposedly committed suicide in different ways. Five prosecutors have been assigned to the investigations. However, many old and new questions surrounding the cases still remain unanswered. According to legal sources, with the exception of Halim Ünsem, Ünal is said to have committed suicide as a result of psychological problems, but none of the engineers have been reported as having received psychological treatment. All of the cases have one thing in common: Each and every engineer was an expert in their field and working on military projects that would most probably decrease the TSK's external dependence.

That the previous seven cases, in one way or another, have remained unsolved should push for Parıldar's case to be investigated meticulously. Did Parıldar really commit suicide? If so, why? What are the links in all of the ASELSAN cases? If Parıldar did not end his own life, as his friend believes, then what was the motive behind this act? Those are some short questions that require detailed answers as soon as possible.