The arrest Thursday night, the first in the case, followed interrogation of Malli the past few days. Sources said she allegedly refused to cooperate.
Malli has been charged with conspiracy, corruption and causing loss to the exchequer. She allegedly received Rs 18 lakh commission from SIFL for the mediation, the sources said.
CBI had registered FIR against M Shahnavaz, MD of SIFL, company senior manager Valsan and Malli for allegedly colluding with officials of the heavy vehicles factory at Avadi and bagging contracts at highly inflated rates, causing loss to the state exchequer.
The case was registered after searches on January 15 and 16 at the residences and premises of the suspects in Kerala, Mumbai, Avadi and Hyderabad.
SIFL is a regular supplier of road wheel arm and flange used in the manufacture of artillery tanks.