The Anti-Terrorist Squad on Sunday arrested Raees Ahmed for his complicity in the September 8 blasts in Malegaon that killed 31 people.
He was produced before a special MCOCA court that remanded him to police custody till November 16.
"Raees is a conspirator and a bomb planter," said a senior ATS official.
He is the brother-in-law of Shabbir Ahmed Masiullah alias Shabbir Batterywala, the prime conspirator, and was earlier arrested for his role in a September 13 bomb hoax at Malegaon.
Over 300 were injured in four blasts that rocked the powerloom town on the occasion of Shab-e-Barat.
Raees is a resident of Malegaon and a suspected Students Islamic Movement of India activist, ATS officials said.
This is the third arrest in connection with the Malegaon blasts.
Earlier, Noorul Huda Samsudoha and Shabbir Batterywala were arrested.