The IAAF has confirmed Jama Aden - the coach of Genzebe Dibaba - was arrested in Spain on Monday following an investigation with the Spanish National Anti-Doping Agency.
Spanish police reportedly raided Aden's hotel earlier near Barcelona and the 53-year-old was detained as part of the ongoing investigation.
Aden is one of the top coaches in athletics with Dibaba his most high-profile client, the world champion over 1500metres having been named IAAF World Athlete of the Year in 2015.
In a statement the IAAF confirmed Aden had been arrested, and vowed to assist the authorities with their investigation, it read:
"The arrest today of distance running coach Jama Aden follows a lengthy investigation by the IAAF which began in 2013, working in close cooperation with Interpol, the Spanish authorities including the Spanish National Anti-Doping Agency [AEPSAD], Spanish police and other organisations.
"The IAAF will use all available resources and powers to protect clean athletes and the integrity of our sport.
"This includes targeting and investigating individuals and coaches who are intent on exploiting athletes and promoting the use of prohibited substances."