The main accused in the multi-crore IMA scam Mansoor Khan was arrested by the Enforcement Directorate (ED) said a special investigation team after he landed in New Delhi from Dubai at about 1:50 am on Friday.
The SIT had said that its sources in Dubai persuaded Khan to come back to India and submit himself before the law.
A lookout circular (LOC) was issued against him by both SIT and ED and he would be handed over according to procedure, it said.
Mansoor Khan is accused of cheating thousands of investors by offering investment options in keeping with Islamic laws and promised big returns.
He fled India in June leaving investors in panic. On Monday he released a video saying he wanted to return to India. Earlier, he had released an audio threatening to commit suicide due to a financial setback and harassment by politicians. He had accused Congress MLA R Roshan Baig of taking Rs 400 crore and not returning it.