At the English-language Indian Express, investigation work into the Panama Papers took place amid such tight secrecy over the space of eight months that the reporters involved were not even told the name of law firm Mossack Fonseca.
More than two dozen journalists were roped in to help, but only a core team of three journalists led by Ms Ritu Sarin, executive editor (news and investigation), and top editors including the newspaper's chief editor Raj Kamal Jha, knew about the full scope of the investigations and about the hundreds of thousands of pages of leaked documents. Some of the transactions went as far back as the 1970s.
The Indian Express, which has correspondents or bureaus in many states and is published in more than a dozen cities, is a well-respected newspaper with a long tradition of investigative journalism.
"The investigations were done by three Delhi editors (working full time) and lots of state correspondents. I sent the address list (of the account holders/beneficiaries) for physical confirmation to the state correspondents.... and they had to verify and do small profiles," Ms Sarin told The Sunday Times.
"They didn't know about MF (Mossack Fonseca). They only knew it was a black money story," she said of the reporters helped in the investigation.
Ms Sarin, who is a member of the Washington-based International Consortium of Investigative Journalists (ICIJ), said the investigation was "time-consuming" as the documents were released in spurts. "We (the core team of three) did nothing else for eight months," she added.
The Indian Express was one of the more than 100 news organisations, involving over 350 journalists, working on unveiling hidden financial dealings of world leaders, public officials, celebrities and sports stars. After poring over 36,000 files, its team uncovered more than 500 names of rich and famous Indians who had offshore companies set up by the Panamanian law firm.
These included top Bollywood actor Amitabh Bachchan and his daughter-in-law Aishwarya Rai Bachchan, an actress and a former Miss World, as well as billionaire property tycoons Kushal Pal Singh and Sameer Gehlaut.
Ms Rai has dismissed the report as "totally untrue" while others have denied any wrongdoing.
"The problem was that for each account holder, the documents were disparate, some going into hundreds of pages. (Identifying people) like Aishwarya Rai was easy as all her family members' names were there so you could confirm the identity. But for others, there were just passport numbers or e-mails," said Ms Sarin. "There was a lot of confusion."
Prime Minister Narendra Modi, who took power in 2014 pledging a crackdown on black money, has ordered a federal multi-agency investigation into Indians named in the Panama Papers for possible wrongdoing.
The Indian Express team also worked closely with other journalists, sharing information on an interactive online forum on different topics such as defence deals, India and Iceland.
"This kind of thing is no fun if it is not interactive... You can't work in isolation," said Ms Sarin.