Detectives raided the home of India’s former air force chief on Wednesday as part of an investigation into alleged bribes paid to secure a $748 million contract for 12 Italian helicopters.

Central Bureau of Investigation (CBI) spokeswoman Dharini Mishra said former air chief marshal S.P. Tyagi’s home was among more than a dozen addresses targeted in the raids. “He is one of 13 people we have filed an FIR (First Information Report) against,” Mishra told AFP. The FIR filed on Wednesday represents the first stage of an official police enquiry. The CBI had filed a “preliminary enquiry” report last month into the alleged scandal, then linking four companies, four Westerners and seven Indians to the bribery allegations.