(NewsNation) — Journalist Ross Coulthart told NewsNation he suspects there will be multiple public hearings in the wake of whistleblower David Grusch’s UFO claims.

“You have to wonder at what stage does the president intervene?” Coultlart asked during an appearance Wednesday on “Elizabeth Vargas Reports.” “I think it’s catastrophic. … I think the government needs to actually consider some kind of admission because the evidence is overwhelming. The weight of witnesses is becoming extremely strong.”

Earlier this month, Grusch spoke exclusively with Coulthart, reporting for NewsNation, and claimed that the government is covering up evidence that UFOs really are extraterrestrial and that he has seen evidence of a secret crash retrieval program. The Air Force veteran alleged the U.S. has even retrieved bodies from other species.

Grusch isn’t the only high-level government official to come forward with claims about UFOs, Sen. Marco Rubio, R-Fla., revealed to NewsNation on Monday. Coulthart said he’s heard from more witnesses since his conversation with Grusch.

“A lot of those people, whilst they deeply admire Grusch for his courage in going public … They’re hoping that within a private hearing of the Congress to give their evidence on camera. … A lot of the evidence that they have to reveal is highly confidential,” Coulthart said.

At the same time, NASA and other government agencies have repeatedly said there is no credible evidence of extraterrestrial activity on Earth, attributing most sightings to natural phenomena or human-made objects.

NewsNation’s Brian Entin contributed to this report.