Akin Tokdenir, 18, was arrested along with his father Ahmet on suspicion of the murder of 16-year-old Onur Sandal, whose body was found in a forest earlier this month.
Sandal, a plumber, was reported missing by his parents in November last year and his corpse was found by forest guards buried in a wooded area in the western city of Denizli.
Akin Tokdenir turned himself to police and immediately confessed to the murder, the reports said. His father, who acted as an accomplice, was later arrested.
His lungs were filled with soil, meaning he had been buried alive, the Hurriyet newspaper reported.
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Surveillance footage obtained by the police showed Sandal being beaten by the father and the son, who took the victim away in a car in a residential neighbourhood of Denizli.
The pair said they committed the murder after Sandal refused to get engaged to his girlfriend despite having a "sexual relationship" with her.
"I'm dying. Tell my mother to give her blessings to me. I have made her suffer a lot," Sandal said as he was pleading for his life, according to the father.
The suspects have yet to be formally charged. It was not clear whether Sandal's girlfriend -- whose identity was not disclosed -- was also punished by her family and what her current situation is.
Turkey has stepped up efforts to stamp out so-called "honour killings" in recent years and toughened penalties.
But such crimes remain frequent within conservative Muslim society and while women make up the majority of victims men can also be targeted.
According to women's activists, 237 women lost their lives in such killings in 2013.