NEWARK, N.J. (CBSNewYork) — The Archbishop of Newark is firing back at a retired Vatican official who is calling for the resignation of Pope Francis.

Cardinal Joseph Tobin says claims by a former Vatican ambassador to the U.S. are full of “factual errors and innuendo.”

One-time Vatican ambassador to the U.S. — Carlo Vigano — claims Francis knew seminarians accused former Newark Archbishop Theodore McCarrick of sex abuse, but chose to lift secret restrictions placed on McCarrick by Pope Benedict.

A journalist who edited Vigano’s 11-page letter says Vigano genuinely believes Francis should resign.

“And he couldn’t have a clear conscience unless he spoke,” said Italian journalist Marco Tosatti.

Returning to Rome from a pilgrimage to Ireland, Francis declined to comment and urged journalists to investigate the claims in Vigano’s letter.

The letter names Newark Cardinal Joseph Tobin as one of those involved in an alleged McCarrick cover-up.

On Monday, Newark Cardinal Tobin decried “the factual errors, innuendo – and fearful ideology of the (letter).”

“We are confident that scrutiny of the claims…will help to establish the truth.”

“There’s a lot of reason to suspect certain elements of the Vigano story,” said Fordham University theologian Dr. Patrick Hornbeck. “I don’t know if we can say they are lies, but maybe they just don’t check out factually.”

For instance, father Matt Malone tweeted out a list of public appearances McCarrick made with both Benedict and Vigano at a time when he allegedly was sanctioned to stay out of the public eye.

Vigano believes Francis is “soft” on church doctrine against homosexuality and same-sex marriage.

“Vigano seems to be aligned with certain factions in the Vatican that have never been happy with Pope Francis,” says Hornbeck. “Now does that mean everything in the letter is false? Not necessarily.”

To get to the truth, U.S. bishops are asking the Vatican for a full investigation into all aspects of the McCarrick Case. The president of the U.S. Bishops, Cardinal Dinardo of Houston, says any Vatican investigation must include a panel of lay people with independent authority to seek the truth.