Boy was mauled to death, his sister managed to escape and raised alarm.
New 'bear security rules' follow mailings of humans from hungry animal in remote towns and villages.
In earlier case, brown bear plundered graves and ate human remains.
Schools and kindergartens ordered to keep students indoors in Kirovsky.
The recording comes as several people get killed and wounded in recent 'worst-ever' bear attacks.
One region has shot 58 ravaging brown bears this year because they intrude too close to settlements, destroying livestock.
This spike of bear cannibalism is reported at the South-Kamchatka nature reserve in Kamchatka.
Moments later he is filmed running at top speed when the beast attacks.
Staff and passengers at Nyagan airport in fear of bear patrolling the runway and trying to break into terminal.
His cries woke other participants, and one shot the bear.