Two senior police inspectors will be assigned to investigate whether any officers provided assistance to the suspects, Interior Ministry officials said. "Depending on the results of the investigation, the necessary legal actions will be taken against any police personnel involved," officials were quoted as saying by daily Radikal. The three Christians -- a German and two Turks -- were killed in the southern city of Malatya on April 18. The killings -- in which the victims were tied up and had their throats slit -- drew international condemnation.
Five people were arrested and charged with murder. The trial started last month but was quickly adjourned until Jan. 14 because defense attorneys requested more time to prepare their arguments.
The Interior Ministry decided to launch an investigation after several newspapers published stories Saturday alleging cooperation between police and at least one of the suspects.
Reports in newspapers quoted two of the suspects, Abuzer Yıldırım and Salih Güler, as saying in their testimony that a third suspect, Emre Günaydın, told them that he had met with police officials and learned about the locations of Christian churches in the city.
"I asked him, 'Who are the police chiefs you were talking to?' He said, 'Don't ask, take it easy'," newspapers quoted Yıldırım as saying.
Similar allegations emerged after the January killing of an ethnic Armenian journalist, Hrant Dink, who was detested by hard-line nationalists because he described the mass killings of Armenians in the early 20th century as genocide, a charge that Turkey denies, insisting those killed were victims of civil war and unrest.
Critics have accused authorities of failing to act on reports of a plot to kill Dink, but there has been no evidence that directly implicates any police or government officials in the slaying of Dink outside his office.
Many Turks are convinced that a phenomenon called the "deep state" -- a network of state agents or ex-officials, possibly with links to organized crime -- periodically targets reformists and what they deem perceived enemies of the state in the name of nationalism.
Christian leaders have said they are worried that nationalists are stoking hostility against non-Turks and non-Muslims by exploiting uncertainty over Turkey's place in the world. Many analysts believe some of the recent killings targeting non-Muslims, including the killing of an Italian priest in Trabzon last year, were attempts directed at derailing Turkey's EU membership process.