Here is the sequence of events surrounding the arrest of two Burmese Reuters journalists
1) MSF's LIMITED survey found over 10,000 (6,700 + 9,000) Rohingyas died many of whom from direct violence in the first month of Myanmar military's so-called "security clearance operations".
'Staggering' Numbers From MSF on Rohingya Killings
14 Dec 2017
http://www.newser.com/story/252854/msf-67k-rohingya-killed-in-one-month.html
2) the two Reuters journalists who were sniffing around mass graves, which could potential provide solid evidence for the got for MSF's LIMITED - as opposed to comprehensive - SURVEY of 600,000 genocide survivors in Bangladesh camps, were detained;
SOURCE: Two Reuters journalists arrested in Myanmar
13 Dec 2017
http://www.bbc.co.uk/news/world-asia-42335097
3) Myanmar military subsequently announced finding of mass graves;
SOURCE: Myanmar bars UN probe as mass grave found in Rakhine
20 December 2017
http://www.bbc.co.uk/news/world-asia-42425217
4) the two detainees "disappeared" initially and temporarily.
SOURCE: Detention extended for Reuters journalists in Myanmar
27 Dec 2017
5) the two journalists emerged defiant in the day they appeared before the court where they were charged with 'obtaining state secrets".
SOURCE: Reuters Reporters Are Charged In Myanmar With Obtaining State Secrets
10 Jan 2018
6) Myanmar military admitted to "participating in the killings of 10 Bengali terrorists who threatened to kill local Buddhists".
SOURCE: Rohingya crisis: Myanmar army admits killings
10 January 2018