It's legal FBI Agents Can Pose as Journalists.

FBI Agents Can Pose as Journalists, Inspector General Says

The FBI also did not violate policy when an agent impersonated an editor with the Associated Press in 2007, the Inspector General found.

https://archive.is/l91qL
http://www.usnews.com/news/articles/2016-09-15/fbi-agents-can-pose-as-journalists-inspector-general-says
It wasn’t until seven years later that the FBI’s methods were revealed: Christopher Soghoian, https://twitter.com/csoghoian an activist and principal technologist at the ACLU, and previously a technologist at the Federal Trade Commission, tweeted a link in October 2014 to internal documents posted to the website of the Electronic Frontier Foundation, which had been obtained through a Freedom of Information Act request in 2011. Buried on pages 61 and 62 were apparent copies of fake Seattle Times news stories the agents were then planning to email.

The Seattle Times broke the story that day. It soon spread nationwide. The Associated Press sent a letter to then-Attorney General Eric Holder, protesting the method. Other newspapers also expressed concern, joined by groups like the Committee to Protect Journalists and the ACLU.
FBI Director James Comey has previously called the practice “lawful and, in a rare case, appropriate:”