MOSCOW (Reuters) - Three Russian TV journalists killed in Central African Republic last month while investigating the activities of a clandestine firm of Russian private military contractors were laid to rest in Moscow on Tuesday.

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Orhan Dzhemal, Alexander Rastorguyev and Kirill Radchenko were killed about 200 km (125 miles) northeast of the volatile African state’s capital Bangui, according to local officials.

The Russian Foreign Ministry has said the three men were killed during a robbery, but colleagues of the dead journalists have launched an investigation into their murders, the circumstances of which they say remain unclear.

“We have been orphaned,” documentary maker Pavel Kostomarov told a group of mourners, many in tears, outside a church in central Moscow following a wake for filmmaker Rastorguyev.

Some of the mourners held the dead journalist’s portrait.

Outside a mosque in northern Moscow, the son of slain journalist Orhan Dzhemal addressed hundreds who had come to pay their respects.

“People like him are rare. If there were just a few more people like him, the world would be a much better place,” Mansour, Dzhemal’s young son, said.

“His whole life was a heroic act, a fight for justice and against oppression,” fellow journalist Maksim Shevchenko told mourners, who had carried Dzhemal’s casket into the mosque.

“He always came to the aid of the weak, he was always on the side of those who were threatened with danger,” said Shevchenko.

Radchenko was laid to rest in a closed ceremony, the Ekho Moskvy radio station reported.

The three men were on assignment for TsUR, an online news organization funded by anti-Kremlin campaigner and former oil tycoon Mikhail Khodorkovsky.

Their trip was fraught with issues from the start. They were forced to change their plans at the last minute, they struggled to communicate with their driver, and had inconsistent contact with their fixer.

Central African Republic has been ravaged by violence, with most of the country beyond the control of its central government.

Russian officials have said the journalists were sent on the mission with inadequate planning for such a dangerous environment. Khodorkovsky has said the journalists were experienced war correspondents who made their own decisions about security and were given the resources they asked for.