What is the co-conspirator rule with regard to hearsay?

The coconspirator rule with regard to hearsay is an
exception to the general rule that hearsay evidence may not be admitted during a
trial.

The coconspirator rule allows a certain type hearsay
evidence to be admitted in a trial.  Under this rule, hearsay evidence is admissible if
it is being offered by a person who was a coconspirator with the defendant in the
trial.  So long as the two people were part of the same conspiracy, and so long as the
actions or statements were made in connection with the conspiracy, the hearsay evidence
can be used against the defendant.