YANGON, February 15 (Reuters) - The office of Myanmar's civilian president on Wednesday said a former military officer is suspected to have hired the killer of a prominent lawyer advising Nobel laureate Aung San Suu Kyi's ruling party, in a likely bid to destabilise the country. The killing in January came at a time of renewed communal and religious tension in Buddhist-majority Myanmar, where a civilian government led by Suu Kyi has ruled for more than 10 months after a formal transition from decades of military rule. A heavy-handed sweep by security forces in Rakhine State, home to many Rohingya Muslims, has led to an estimated 69,000 from the largely stateless community fleeing into neighbouring Bangladesh, the United Nations estimates. The adviser Ko Ni, 63, was a Muslim lawyer who was shot in the head outside Yangon's international airport in a rare act of political violence that rocked Myanmar's commercial capital. In a statement, the office of President Htin Kyaw said former Lieutenant-Colonel Aung Win Khaing, who retired from the army in 2014, was suspected of paying his older brother 100 million kyat ($73,800) to murder Ko Ni. "Aung Win Khaing, who allegedly paid money for the crime and is still on the run, used to work in the military as a lieutenant-colonel until 2014," it said, adding that the 45-year-old left the army for personal reasons. Zaw Htay, a spokesman for the president's office, confirmed the statement. Reuters was unable to contact the suspect's family for comment and it was not clear if he had legal representation. Myanmar's military and police did not immediately respond to requests for comment. Closed-circuit television showed the former army officer at the airport's arrivals hall, checking flight schedules minutes before Ko Ni was shot, the statement said. Later, it said, he sent a text message with details of the lawyer's arrival gate to his older brother, Aung Win Zaw, citing the testimony of the latter, who was detained within hours of the killing last month. Authorities have also detained a suspected gunman, named by police as Kyi Linn, 53, after a group of taxi drivers chased him down. One of the drivers was himself shot and killed. The lawyer's killing was probably motivated by the "intention to destabilise the state", the presidential office said in January. Myanmar's national police chief has taken personal charge of the investigation into the killing, police sources have told Reuters.