Gurugram, Dec 23 : A taxi driver was allegedly shot dead in his car near Manesar on the Delhi-Jaipur Expressway on Saturday morning, the police said. While the exact motive behind the killing is yet to be known, the police suspect robbery could be a reason behind the murder. The deceased's identity is yet to be established, the police said. "Preliminary inquiry suggested that robbery could be a reason behind the killing. But we will know about the motive only after we arrest and question the suspect,' said Subhash Boken, spokesperson for Gurugram Police. The matter came to light after a passerby called the police on seeing the deceased in his car near a dhaba on the Expressway at around 9.30 a.m. When the police reached the spot, they found that the victim had a gunshot wound on his head. A case of murder has been registered at the Manesar police station. /IANS