Former FBI chief James Comey testified on Thursday that if Americans colluded with Russia’s effort to influence the US presidential election, special counsel Robert Mueller will get to the bottom of it.

“If any Americans were part of helping the Russians do that to us, that is a very big deal. And I’m confident that if that is the case, Director Mueller will find that evidence,” Comey told the Senate Intelligence Committee.

The committee is investigating the Russian meddling and whether there was any collusion between the Russians and the Trump campaign.