The CID on Monday arrested a software engineer, Sai Kumar, 28, employed with Mahindra Satyam in the US, when he arrived at Shamshabad airport, for defaming his former colleague by hacking into her email IDs and creating fake Facebook profiles. CID additional DGP S.V. Ramana Murthy said Kumar was taking reven-ge after she spurned his marriage proposal. Kumar told the police that he had become friends with the woman while he was working in Hyderabad three years ago.