The government says Saturday's video containing what appears to be the corpse of hostage Haruna Yukawa is probably authentic, but less certain is whether the same can be said of the voice on the recording claiming in English to be Kenji Goto.

The government is fairly confident it's him, but voice experts are mixed.

Experts who analyzed the recording and compared the speaker's vocal characteristics with verified recordings of Goto speaking English found reasons to believe and disbelieve.