Ömer Halisdemir was born as one of the seven children to Hasan Hüseyin Halisdemir and his wife Fadimeana at Çukurkuyu town in Bor district of Niğde Province, central Turkey, on February 20, 1974. He spent his childhood in his hometown. During his free time after school hours, he worked as a shepherd. After completing the primary and middle school, he was attended and graduated the Industrial Vocational High School in Niğde. He first entered entrance exam for the Police Academy, which he passed. However, since his dream was always to become a soldier, he did not pursue that path further. A relative took him to Ankara for an exam of non-commissioned officer schools. His childhood dream came through when he passed the exam. He married Hatice Halisdemir, with whom he had a daughter, Elifnur, and a son, Doğan Ertuğrul.
2016 coup d'état attempt, killing of Terzi, and death
On the night of July 15, the 2016 Turkish coup d'état attempt, Maj. Gen. Aksakallı heard about the coup attempt as he was not present in the headquarters. His official car was intercepted by three military vehicles on the way to the Presidential Complex. He nevertheless managed to get away from the ambush of the pro-coup troops, which were seeking to capture him. He learned that Brigadier general Semih Terzi, commander of the 1st Special Forces Brigade in Silopi, southeastern Anatolia, was assigned by the coup plotters to take over the Special Forces Command. He quickly ordered his right-hand man, the staff sergeant Halisdemir by phone to take out Terzi in order to prevent this action. Halisdemir simply affirmed the order, which was a fatal task. He took a hiding position in the foliage at the front yard of the headquarters building. Brig. Gen. Terzi and ten heavily armed troops and officers escorting him, who flew in from a military base in Diyarbakır, landed with a helicopter outside the headquarters around 02:16 local time on July 16. Halisdemir came out from his hiding place and joined the crowd marching towards the entrance of the headquarters building. He drew his handgun and shot the general three times in the head, killing him. Halisdemir then tried to run away. MajorFatih Şahin immediately responded with a barrage of fifteen rounds of gunfire, hitting Halisdemir twelve times in the back. Halisdemir's body was carried out of the way. As Lieutenant Mihrali Atmaca noticed that Halisdemir was still alive, he shot him once more, this time fatally. Brig. Gen. Terzi was rushed to the military hospital by helicopter. The capture plan turned into a disarray since the chain of command was broken. The whole event was captured on security cameras. Halisdemir's father later said that "his son served five years for Gen. Terzi, and Terzi thought he could easily take over the headquarters from Halisdemir."
Aftermath
The coup attempt failed nationwide as the rebels were met with a fierce resistance from the public, police and loyalist military. The whole coup attempt was suppressed within the early hours of July 16. The pro-coup military personnel, who tried to capture the Special Forces Command and killed Sgt. Halisdemir, were arrested. Trial of the seventeen officers began on February 20, 2017. They are each facing a life sentence if found guilty. Ömer Halisdemir was buried in his hometown, Çukurkuyu, on July 17, 2016. His funeral was attended by high-ranking local officials and thousands of others.
Legacy
A monument to commemorate Halisdemir and his bravery was erected in the front yard of the Special Forces Command headquarters, where he was killed, next to a spot which contains his preserved blood stain.