Vladimir Putin was seen embracing a convicted killer who could know some of the leader’s most dangerous secrets.

Russian state assassin Vadim Krasikov was released from a German prison as part of a prisoner exchange with the West.

The 58-year-old was crucial to the deal to free Wall Street Journal reporter Evan Gershkovich, falsely accused of spying by Moscow.

When the newly released Russians landed on home soil, Krasikov was the first off the plane and was met by Putin on a specially-lain red carpet.

The leader shook the killer’s hand, hugged him and said ‘zdorovo’, an informal greeting that…