Militant groups including ISIS and Al-Qaeda are active across Africa.
Mali has played host to a raft of extremist groups in recent years but people's reasons for joining are often the same.
McGowan was kidnapped along with a Swede and Dutch national, both of whom have already been released.
The EU is investing $56 million in a counter-terrorism force in a region awash with militant groups.
Some of the groups were involved in the 2012 northern Mali uprising.
Islamic State militant group accepts allegiance of a militia based in a region high in instability and low in security.
Abu al-Nur al-Andalusi had previously encouraged Spanish Muslims to "join the jihad."
President Erdogan is conducting a tour of West Africa to boost trade links.
The group's North African branch planned to stop attacks in return for the release of its prisoners.
The 900 detainees were questioned over various offences ranging from drug possession to traffic violations.
At least 30 people were killed when gunmen attacked a hotel and cafe in Ouagadougou on Friday.
At least 28 people were killed when Al-Qaeda-linked militants attacked a hotel in Burkina Faso's capital on Friday.