(CNN) The IRS is now sharing information with special counsel Robert Mueller about key Trump campaign officials, after the two entities clashed this summer over both the scope of the investigation into Russia's meddling in the 2016 election and a raid on former Trump campaign chairman Paul Manafort's home, people briefed on the matter tell CNN.
Part of the concern centered on the far-reaching and broad requests from Mueller's team. In the case of Manafort, Mueller's investigators are reaching back 11 years as they investigate possible tax and financial crimes, according to search warrant documents. Mueller is bound by a written order issued by Deputy Attorney General Rod Rosenstein in May which allows the special counsel to investigate "any matters that arose or may arise directly from the investigation."
After several months of being at odds, one source said, the IRS Criminal Investigation division is now sharing information about campaign associates, including Manafort and former White House national security adviser Michael Flynn. The sharing happened after the two camps reached an agreement following consultation with officials at the Treasury Department.
CNN has learned the IRS Criminal Investigation agents had been working with the FBI to investigate Manafort since before the election in a similar probe that centered on possible money laundering and tax fraud issues, according to the sources. It's unclear if Flynn is now or was previously under investigation by the IRS. CNN has reported that Mueller's team is examining Flynn's payments from Turkey and Russia.
A former high-level Justice Department official says the information shared would include anything tax return-related such as real estate and banking records. The former official added the IRS is very restricted in what information it can share under Title 26 US Code and would normally need a specific grand jury subpoena in order to share tax returns with another agency.
The new information about the depth of IRS involvement renews questions surrounding the controversial issue of President Donald Trump's tax returns, which he refused to release during the campaign despite decades of precedent by presidential candidates.
It is not clear whether the special counsel has asked for or obtained Trump's tax returns. Sources say if Mueller's office does have Trump's returns, then Rosenstein, who oversees the probe, likely would have needed to sign off, given the sensitivity surrounding the matter.
Tension between the IRS and the special counsel played out behind the scenes of the high-profile raid on Manafort's Alexandria, Virginia, home this summer, according to multiple sources.
CNN has learned that the IRS did not participate in the July raid by FBI agents in part because of IRS objections that the search would interfere with the separate IRS investigation of Manafort, according to people briefed on the investigations.
The special counsel's office decided to proceed with the search on Manafort's home with only FBI agents carrying it out, the sources said.
The absence of IRS criminal investigations agents for the raid is unusual for a probe that centers on tax and financial matters. As CNN has previously reported, during the raid the FBI collected tax and other financial documents from Manafort's home, according to search warrant documents in the Manafort raid. The search warrant documents said the scope of the investigation includes possible crimes beginning January 1, 2006, a source told CNN.
Manafort has previously denied financial wrongdoing regarding his Ukraine-related payments, his bank accounts in offshore tax shelters and his various real estate transactions over the years.
The complications could continue in the event Mueller's team brings charges against Manafort and others under investigation. Mueller's team has warned Manafort that they are working to charge him with possible tax and financial crimes, sources previously told CNN, an indication the investigation could be in an advanced stage.
Flynn's lawyers have previously criticized media reports about his connection to the Russia investigation as peddling "unfounded allegations" and "outrageous claims." Flynn's lawyer declined to comment for this story. Manafort's lawyer didn't immediately comment for this story.
The IRS Criminal Investigation division and the special counsel's office declined to comment.