The man accused of murdering an environmentalist couple in southwestern Turkey has committed suicide in prison, where he was being kept while awaiting trial.

31-year-old suspect Ali Yumaç previously confessed that an individual linked to a stone quarry, one of many in the region that the couple was fighting against, had hired him to commit the murder.

The prosecutor's office in the Alanya district of southern Antalya province announced Wednesday that Yumaç was found dead in his ward after a suspected suicide early in the morning. Yumaç's body was transferred to Antalya for autopsy, the statement added.

He was expected to shed more light on the murder, and the quarry industry's role in the couple's death, during the trial. i

The couple, Aysin and Ali Ulvi Büyüknohutçu, both 61 years old, were found murdered in their rural home in the Finike district of Antalya province on May 10. Büyüknohutçu was best known for his activism and lawsuits against stone quarries in Finike and the rest of Antalya, in addition to being the chairman of a tenants' rights association and a consumer rights workgroup within the Antalya City Council.

Yumaç was detained on May 10, the night of the murder, and he was first transferred to a prison in the Elmalı district, and later Alanya, where he was held pending trial. He was first detained as a suspect in the murder, but he later confessed to killing the couple in his testimony before the gendarmerie. Yumaç initially claimed that he came to the couple's home on Tuesday to ask for money for the treatment of his sick wife, but shot the couple with a hunting rifle after an ensuing argument.

Yumaç said that a 65- or 70-year-old man working in the quarry approached him on May 8, gave him TL 3,000 in advance and promised the rest of the money after the murder. Yumaç's testimony said that the man wanted him to portray the murder as theft and throw the weapon and everything else into a deep sinkhole located some two kilometers away from the crime scene. He also gave a detailed account of the man's physical characteristics and his license plate number, saying that they were supposed to meet for the remainder of the money in a quarry after the murder, but the man did not show up.

Yumaç also said that he intended to kill only Ali Ulvi, but when the man held a flashlight in his face he panicked, killing both the man and the woman. He added that him and his wife had gone to the couple's house as guests for tea, letting him plan the murder for that location.

However, in his testimony before the public prosecutor and the court, Yumaç confessed that a man who had worked at a quarry that was later shut down, whom he identified with the alias "Çirkin" (Ugly), offered him 50,000 Turkish liras ($13,780) for the murder of the Büyüknohutçu couple.

Since Yumaç committed suicide in prison, the investigators have lost a key player in understanding the motives behind the couple's murder, as well as the crime's links to the quarry industry.

With the help of locals and environmentalists, the Büyüknohutçus had been fighting against local stone quarries for the last six years in Finike's Alacadağ, Gökçeyaka, Kızılcık and Adala villages, which are located among centuries-old cedar and pine forests. In return, the couple experienced constant harassment related to their activism, according to their friends' accounts.