More than seven months after an arrest warrant was issued for Akın İpek, a prominent Turkish businessman linked to the shady Gülen Movement, Akın's younger brother Cafer Tekin İpek was detained in his Istanbul villa late on Sunday. Similar to Akın İpek, who built a business empire with his brothers and mother from a smaller printing business, the ounger İpek faces charges of aiding the so-called Gülenist Terror Organization, also known as FETÖ.

FETÖ, which prosecutors believe is led by U.S.-based former cleric Fethullah Gülen, is accused of two attempts to seize power by coup as well as other crimes including fraud, money-laundering and illegal wiretapping. Akın İpek was reportedly in the United Kingdom when an arrest warrant was issued for him, and is still believed to be there, while authorities have seized his assets in Turkey and trustees were appointed to his conglomerate, including printing, media and energy companies. FETÖ originates from the Gülen Movement, which evolved from a faith-based group into a politically-motivated juggernaut, one which relies heavily on aid from Turkish business world, some of whose members have pledged allegiance to Fethullah Gülen.

Turkish authorities have stepped up their crackdown on FETÖ financiers. Last week, police rounded up 105 suspects in Istanbul and eight other suspects during operations against the financing of FETÖ. Board members of a well-known construction company and employees of Bank Asya, a lender linked to Gülenists, were detained. Prosecutors accuse them of committing fraud from charities linked to the Gülen Movement under a scheme called "himmet."Himmet refers to money collected as charity from unsuspecting followers of the Movement, which prosecutors allege is then secretly funneled to Gülen-linked companies to finance the terrorist organization's illegal activities. Gülenists operate a vast network of schools and charities, and finance illegal activities with funds supposedly collected for charitable purposes.