According to this, Diack's sons asked for a $500,000 bribe to cover up Alptekin's doping positive from when she won gold in the women's 1500m at the London Olympics:
Slightly cleaned up from Google translate:
During their talks, investigators hired by the AMA have discovered a new case, never publicized, not Russian. Olympic champion of 1500 meters in London, the Turkish Asli Alptekin, was also the victim of blackmail orchestrated by the family Diack. The two sons of the former head of the International Athletics Federation asked her for 500,000 dollars in November 2012. Refusing blackmail, the athlete was eventually sentenced to an eight-year doping ban in July 2015,surrendering her Olympic gold medal from 2012.
The IAAF website still hosts the ridiculous story that the gold and silver in the 1500 were the result of "Turkish girl power":
It will take a major change for track and field to regain any credibility.