Areeb Majeed had disappeared in May from his home in Kalyan, a suburb on the eastern outskirts of Mumbai.
Areeb Majeed, 23, who travelled to Iraq to join the Islamic State group has told investigators that the jihadists made him clean toilets and do other menial jobs, according to the Press Trust of India.
Majeed, who returned to Mumbai on Friday and was arrested on Saturday on terrorism charges, is being extensively interrogated by members of the National Investigation Agency or NIA, the country's top counter-terror body.
Unnamed sources in the NIA told the Press Trust of India that Majeed "revealed the names of the local contacts, who radicalized him and his three other friends here, and helped them fly to Iraq. We are verifying his claims and are trying to locate these contacts."
Majeed left for Iraq with three friends in late May from Kalyan on the eastern outskirts of Mumbai.
He phoned his family to say he wanted to come home after suffering an unexplained bullet wound for which he did not get proper medical attention, PTI said late Sunday.
"Only after I begged them, I was taken to a hospital," he was quoted as saying by NIA officers.
"There was neither a holy war nor any of the preachings in the holy book were followed... ISIS fighters raped many women there," he was quoted saying.
Top officials including Home Minister Rajnath Singh have spoken of the threat of IS militants attempting to recruit from India's large pool of young Muslim men.
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Al-Qaeda announced in September a new chapter of its extremist movement charged with waging jihad in South Asia, prompting several Indian states to be placed on high alert.