Intelligence reports in South Korea had suggested Ri Yong-Gil, former chief of the Korean People's Army (KPA) General Staff, was executed in February on accusations of corruption and forming a political faction.
Although the reports were never confirmed by Pyongyang, North Korea named a new chief of staff, Ri Myong-Su, in the same month.
The change came at a time of highly elevated tensions on the divided Korean peninsula following the North's nuclear test in January and long-range rocket launch.
Reports -- some confirmed, some not -- of purges, executions and disappearances have been common since Kim Jong-Un took power following the death of his father Kim Jong-Il in December 2011.
A large number of senior officials, especially military cadres, were removed or demoted as the young leader sought to solidify his control over the powerful army.
In the most high-profile case, Kim had his influential uncle, Jang Song-Thaek, executed in December 2013 for charges including treason and corruption.