It was a bombshell moment in the biggest American political scandal ever.

Federal Grand Jury indicts seven mix and aides on charges of conspiracy on watergate,

halledmen, early men, Mitchell, on list, declared the front page banner headline in the New York Times.

It was March 1, 1974, and special prosecutor Leon Jaworski, who had taken over for the fired archibald cogs

lessons six months earlier, had finally hit paydirt.

Mitchell, president Nixon's former attorney general, halledmen, his ex chief of staff,

and early men, his former chief domestic advisor, were all accused of multiple crimes,

lying to Congress and the FBI, conspiring to pay hush money and obstruct justice.

What was not known at the time and wasn't revealed until months later,

is there was a secret part of the indictment, naming president Nixon himself as an unindicted

co-conspirator. Why unindicted? And why was it kept from the public?

We'll explore those questions and what they could mean for Robert Mueller's Russia investigation

on today's buried treasure.

I'm Michael Rizikov, chief investigative correspondent for Yahoo News.

And I'm Dan Clydeman, editor in chief of Yahoo News.

You know, Danny, I know folks like you are too young to actually remember all this,

but somebody like myself in college at the time, a total watergate junkie,

this was a real seminal moment in the watergate saga.

It had been playing out for nearly a year, more than a year actually,

before that, the Senate watergate hearings, the Saturday night massacre.

But when you had actual indictments of the top aides to the president of the United States,

it became clear this wasn't going to end.

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