Gandhi, a Politbureau and Central Committee member of the banned CPI (Maoist), was in Delhi for the past three years.
“He has been with the CPI (Maoist) for last many years and was in-charge of expanding the party in urban areas," a senior police official said.
He “is widely acknowledged as an ideologue and was also in-charge of the party"s publication wing, and played a crucial role in getting international recognition to the party."
The police were checking his visits, mobile phone details and accounts to know about his contacts in Delhi.
The police, however, did not divulge from where they arrested him or what was recovered from him.
Gandhi worked in Maharashtra, Andhra Pradesh, Jharkhand and Madhya Pradesh.
Gandhi would now be handed over to Jharkhand Police.
“The Jamshedpur police officials have been informed about his arrest and they may arrive in a few days to take his custody,"said a police official.
"Till now, we have not found him involved in any unlawful activity in Delhi but we are trying to know if he had any link with any Maoist arrested in Delhi earlier."