18:00Six O'Clock News21/01/2016 Litvinenko's death "probably" approved by PutinBBC Radio 4 Duration: 30 minutes Thu 21st Jan 2016, 18:00 on BBC Radio 4 FMAvailable for over a yearListen nowPublic inquiry into former spy's killing concludes senior Russian officials were involvedGenresNewsFormatsBulletinsBrandSix O'Clock News Source: BBC Online