Patna: Family members of Kumar Ajitabh, the 30-year-old engineer missing from Bangalore since December 18, suspect he has been kidnapped by criminals posing as car buyers on online marketplace OLX.

The family, which lives in Patna, has told the Bangalore police that Ajitabh, who was working with British Telecom, is missing from Monday evening after he left his flat to meet a prospective buyer of his car. Ajitabh's father A.K. Sinha and some relatives are camping in Bangalore.

His family members and friends have also started a social media campaign with the hashtag #FindAjitabh. The family wants to meet the Karnataka home minister.

"My son, who is soon to shift base from Bangalore to Calcutta as he has received admission at IIM Calcutta's executive programme, had uploaded an advertisement about sale of his new Maruti Ciaz car," Sinha told The Telegraph on Monday. "On (last) Monday evening at around 6.30pm he left from his flat, located in the Whitefield area of Bangalore, to meet a prospective buyer. Ajitabh's friend told me that he went out in casual dress and slippers. His friend told us that he went towards Tamil Nadu, but later his mobile became switched off."

Sinha, a former banker, suspects Ajitabh has been kidnapped. However, the family members have not received any ransom call.

The father said Ajitabh had applied for an educational loan of Rs 5 lakh to pay for his IIM fees. He was also planning to sell his car to meet the educational expenses.

"The police are claiming they are investigating from all angles. They have gone through footage of CCTV cameras on the highways and have also sought data from online classified portal OLX. But till now there is no progress in the case," Sinha said.

The Sinhas live in the Kadamkuan area of Patna. Ajitabh did his schooling in Patna and Bokaro, and earned his engineering degree from Manipal University.

After completing his engineering he got a job at TCS and later joined British Telecom. Ajitabh has been living in Bangalore for the past seven years.