In a controversial decision a German court yesterday decided to release M.S.F, a suspect and the instigator behind the murder of Yunus Koca, former Diyarbakır head of the Justice and Development Party's (AK Party) youth wing, in 2015.

On Aug. 31, 2015, a group of assailants opened fire on a pharmacy in southeastern Turkey's Diyarbakır, killing Koca.

Although no one claimed responsibility for the attack, it was supposedly carried out by the outlawed terror group PKK, which has assassinated many other local politicians in recent years for refusing to adhere to its policies in southeastern Turkey.

Turkish police arrested two suspects for the killing, identified by their initials B.B., 19, and M.A., 46.

Both B.B., who pulled the trigger, and M.A., revealed during investigation that they killed Koca at the instigation of M.S.F., in return for money. After a range of operations on his house and workplaces, it is revealed that M.S.F. had fled abroad with a fake passport. After the incident, police also started to investigate the suspects' possible connections with the PKK.

While B.B. and M.A. were arrested in Köln in 2016, a red notice was issued for M.S.F by the Interpol Head of Department.

Later the same year, M.S.F. was caught in Köln and arrested by the German police. His extradition process was then initiated.

However, this year, after holding M.S.F. in a Köln prison for a year and accepting Turkey's extradition demands, German authorities released him.

Meanwhile, the Interpol Head of Department intervened in the issue and demanded the extradition of the suspect to Turkey in accordance with the extradition agreement between the two countries.

The issue likely will become the latest in a string of incidents that have caused tensions between Turkey and Germany.

Recently, in the wake of the failed July 15 coup attempt, Germany has been accused by Ankara of granting political asylum to a number of Turkish military personnel and their families who hold diplomatic passports and have suspected links to the Gülenist Terror Group (FETÖ).

The Incirlik base crisis was another important issue between the two countries as Berlin has recently hardened its tone against the Turkish government over İncirlik Air Base spat and threatened to pull out after German lawmakers were denied entry to the base.

In addition, Turkey has long criticized Germany for not taking serious measures against the PKK terror group.

During campaigns on the Turkish constitutional referendum, German officials allowed terrorist PKK followers to march in Frankfurt, in contrast to its barring of Turkish ministers and politicians from addressing Turkish voters in the country.