He was captured in his car, moments after having fled his villa in Cengelkoy on the Asian side of Istanbul, local media has reported.
The Istanbul prosecutor's office has labelled Oktar's group a criminal gang and said it aimed to commit crimes including sexual abuse of children, sexual assault, money laundering, depriving people of their freedom, fraud, bribery and torture, state-run Anadolu said.
The preacher began forming groups of followers in the late 1970s and has frequently run afoul of Turkish authorities. He has faced a number of trials, including on previous charges of forming a criminal gang, but was acquitted.
The broadcasting regulator suspended one of his programmes in February, saying its blend of theological discussion and dancing violated gender equality and women's rights.
Oktar, who argues that Darwin's theory of evolution is the root of global terrorism, has previously accused British intelligence of requesting the Turkish authorities to take action against him.
According to his website, Oktar has written more than 300 books, translated into 73 languages. Under his pen-name Harun Yahya, he gave secularist France a scare in 2007 by mass-mailing thousands of free copies of his "Atlas of Creation" to schools and libraries across the country.
The Education Ministry ordered school headmasters to seize and remove copies of the glossy book, which argues that all living things were created by God exactly as they are formed today.
(Writing by Humeyra Pamuk; Editing by David Dolan and Angus MacSwan)
https
://uk.reuters.com/article/uk-turkey-security-arrest/turkish-televangelist-and-followers-jailed-pending-trial-on-sex-abuse-fraud-charges-anadolu-idUKKBN1K90ZP