An ED official told IANS that Rajesh Agarwal was arrested from Delhi for alleged money laundering and involvement in the black money racket.
Agarwal was accused of converting black money through dubious transactions with the help of two bothers S.K. Jain and V.K. Jain. The ED had arrested the Jain brothers on March 20.
At least 90 shell firms were under the ED scanner.
Agarwal has also been accused of helping Bharti's husband's company, Mishail Packers and Printers Pvt Ltd.
The arrest follows the May 16 Income Tax raids at 22 places in and around Delhi in connection with alleged "benami" property deals involving Lalu Prasad and his children - Bihar Deputy Chief Minister Tejashwi Yadav, Health Minister Tej Pratap Yadav and Misa Bharti, who is also Rajya Sabha MP.
Agarwal will be produced in a Delhi court later in the day.