Four gunmen shot dead a senior investigative journalist specialising in organised crime in the Indian city of Mumbai on Saturday, police said. Jyotirmoy Dey, 50, was killed at 2.30pm near his home in the city\'s Powai district, and the gunmen escaped on motorcycles, said the official, who did not wish to be identified. Dey led a team of crime and investigative reporters at the Mid Day newspaper and had written books on different gangs involved in organised crime in Mumbai. \"He brought depth to our investigative reporting, and he conducted his journalism with honesty and integrity,\" Sachin Kalbag, executive editor of Mid Day, said in a statement. Information and Broadcasting Minister Ambika Soni said the assassination was a challenge to the freedom of the press. Prithviraj Chavan, chief minister of the state of Maharashtra, said the government was determined to track down the assailants. Dey was shot five times at point-blank range in Mumbai\'s Powai suburb, Mid-Day chief reporter Vinod Kumar Menon said. Police said they were discussing Dey\'s recent work at the newspaper to try to identify suspects and the motive for the attack. They said the four gunmen escaped aboard two motorcycles. \"We are in a state of complete shock,\" the Press Trust of India quoted editor Sachin Kalbaug as saying. \"It is too early to say why this has happened and how it happened. No indications that he was working on a big story which would have made anyone uncomfortable.\" Dey had long worked as a journalist, writing for the Hindustan Times and the Indian Express before joining Mid-Day, where he was seen as a crime-reporting \"guru\" to younger staffers. \"He was a most senior and respected journalist,\" Menon said.