President Donald Trump's former campaign chairman, Paul Manafort, alerted authorities in June about Donald Trump Jr.'s controversial Trump Tower meeting with a Russian lawyer during the 2016 presidential campaign.

Knowledge of the June 2016 meeting became public with a New York Times report last month. Authorities, however, were informed of the meeting by Manafort a month prior, on June 9, Bloomberg reported Thursday.

Trump Jr.'s meeting with Russian lawyer Natalia Veselnitskaya included Manafort, Trump's son-in-law and senior adviser, Jared Kushner, Russian political operative, Rinat Akhmetshin, and Russian real estate executive, Irakly "Ike" Kaveladze.

Rob Goldstone helped broker the meeting, claiming that Veselnitskaya could provide him with compromising information against Hillary Clinton as part of Russian government's efforts to help Trump's candidacy, according to the New York Times.

The documents "would incriminate Hillary and her dealings with Russia and would be very useful to your father," read the email, written by a trusted intermediary, who added, "This is obviously very high level and sensitive information but is part of Russia and its government’s support for Mr. Trump." If the future president's elder son was surprised or disturbed by the provenance of the promised material—or the notion that it was part of an ongoing effort by the Russian government to aid his father's campaign—he gave no indication. He replied within minutes: "If it's what you say I love it especially later in the summer."

Manafort has, in addition to informing authorities of the meeting, been voluntarily providing documents to congressional committees conducting separate investigations into Russia’s election interference, the Washington Post reported.

In conjunction with the special investigation led by special counsel Robert Mueller, FBI agents raided Manafort's Alexandria home late last month. Agents seized materials and documents related to the investigation, according to the Post.

The raid, which occurred without warning on July 26, signaled an aggressive new approach by special counsel Robert S. Mueller III and his team in dealing with a key figure in the Russia inquiry. Manafort has been under increasing pressure as the Mueller team looked into his personal finances and his professional career as a highly paid foreign political consultant. Using a search warrant, agents appeared the day Manafort was scheduled to testify before the Senate Judiciary Committee and a day after he met voluntarily with Senate Intelligence Committee staff members. The search warrant requested documents related to tax, banking and other matters. People familiar with the search said agents departed the Manafort residence with a trove of material, including binders prepared ahead of Manafort’s congressional testimony.

The search warrant indicated that investigators may have argued Manafort could not be trusted to turn over all records in response to a grand jury subpoena.