The free eBook, released yesterday, features advice and expertise from media organisations such as the BBC, Der Spiegel and Eliot Higgins' Bellingcat.
The Tow Center for Digital Journalism also offered input into the 10-chapter book, as well as civil society organisations including Amnesty International, WITNESS and the verification platform SAM.
"The amount of information that is available for free in databases, online, on social networks and other places... it's amazing what can be done through that sort of open source and publicly available information," said Craig Silverman, who edited the latest handbook as well as the previous one.
The original Verification Handbook, which has been downloaded 50,000 times since its launch in January last year, focused on verification for breaking news coverage.
The Verification Handbook for Investigative Reporting develops this further by highlighting search and research techniques specifically for online investigations as well as best practice for verifying open data and fact-checking.
And with user-generated content (UGC) and eyewitness media increasingly being incorporated into news reports, it also provides expert advice for ethical approaches to using this type of content in investigations, including crediting and ensuring "duty of care" to sources and uploaders.
"A lot of times, unfortunately, people just view [UGC] as material, and these folks are just sources," said Silverman.
"And that's really not the case, they're folks who are sometimes putting themselves in danger, who have put themselves at risk to put this information out there. They are sometimes people who, if you give them bad direction, they may end up putting themselves in harms way without realising it.
"So it's really important in newsrooms for people to start realising that yes, this information is tremendously valuable, but it's not just yours for the taking. You have to think about their rights, about ethics and about their safety and security as well."
The Verification Handbook for Investigative Reporting can be downloaded for free at verificationhandbook.com/book2.