Reuters journalists Wa Lone (center, front) and Kyaw Soe Oo are escorted by police. (Lynn Bo Bo/EPA-EFE/Shutterstock)

“WE ARE not doing anything wrong. Please help us by uncovering the truth.” Those words on Wednesday from Kyaw Soe Oo, on the steps of a courthouse in Rangoon, Burma, are an apt description of a test case for the nation’s democratic aspirations. Mr. Kyaw Soe Oo is a Reuters reporter and, with a colleague, Wa Lone, has been imprisoned and charged with carrying out the “crime” of investigative journalism. They must be freed if Burma, also known as Myanmar, is to sustain even a shred of respect for democracy.

The two journalists were investigating reports of a mass grave in Rakhine state, where the Burmese military has conducted a scorched-earth campaign against the Muslim minority Rohingya population. Long marginalized by the majority Buddhists, the Rohingya have in recent months been subject to ethnic cleansing from their villages, propelling about 650,000 into exodus in neighboring Bangladesh, where they are crowded into camps. Human rights monitors say the campaign brought murder, rape and destruction to the Rohingya villages.

The journalists were looking into reports of a mass grave in the village of Inn Din. Reporting such as this has been extremely difficult because of government restrictions on journalists and independent investigators. The journalists were arrested Dec. 12 after being invited to meet police officials on the outskirts of Rangoon, where they were first given some documents, then almost immediately taken into custody. The government has said the reporters “illegally acquired information with the intention to share it with foreign media.” On Wednesday, they were formally charged with obtaining state secrets and violating the Official Secrets Act, a British colonial-era law with a maximum sentence of 14 years in prison.

Later Wednesday, the military released results of its investigation into the mass grave the journalists were probing. A statement said that 10 bodies there were of Muslims who had been killed by villagers and security forces “because they were terrorists.” The Burmese military campaign was triggered by an August attack on security posts by a small Rohingya militant group, but the military’s statement about terrorism should be viewed with acute skepticism. The truth is still elusive. The Reuters journalists were chasing it, and putting them in jail was to prevent them from finding it.

Burma’s military remains a powerful force in the country, even though it has passed partial control to civilians, now under the leadership of the Nobel Peace Prize laureate Aung San Suu Kyi. Her weak response to the Rohingya operation may be explained by the military’s continued dominance of security matters, but she should not tolerate the prosecution of the two reporters. Already, journalists complain there has been serious backsliding of press freedom under her government. She must stand up for a free press as the core of a free society, demand release of the Reuters pair and allow unfettered access to Rakhine state.