WASHINGTON – Manhattan District Attorney Cyrus R. Vance Jr. has convened a grand jury for his far-reaching investigation into former President Donald Trump, the Washington Post reported Tuesday, citing two sources familiar with the probe.

Prosecutors have been investigating Trump, the Trump Organization and its officials since at least 2018. The grand jury signals that they are ready to produce evidence and possibly bring charges.

The panel was recently convened, according to the Post, but it wasn’t clear when exactly. She will meet three days a week over a period of six months.

A Trump spokesman did not respond to a request from CNBC for a response on the legal developments. However, Trump himself issued a statement later that evening calling the investigation “purely political” and promising to “keep fighting”.

In New York State, this type of special grand jury typically hears a number of different cases and is particularly useful on complex, long-term matters.

Although much of Vance’s investigation is still opaque, court records and witnesses have confirmed that prosecutors are investigating various types of financial activity that Trump and the Trump Organization have been involved in.

One is whether the former president and his company mistakenly increased the value of their properties for insurance specialists and then undervalued the properties for tax purposes.

Another area of ‚Äč‚Äčinvestigation is how the Trump Organization paid its top executives and whether taxes were paid on various forms of compensation.

Earlier this year, Vance and his team won a lawsuit over Trump’s tax returns that they had cited from the company that prepared them.

The former president has repeatedly and emphatically denied any wrongdoing. He has accused the prosecutor of conducting a politically motivated investigation.

New York State Attorney General Letitia James is also investigating the Trump organization in a criminal capacity.

The attorney general’s office had initially opened a civil investigation into the Trump organization. Earlier this month, James’ spokesman announced that the case had turned into a criminal investigation.

For more information on the Trump Grand Jury, see the Washington Post full story.