Former top CIA official told us what he really thinks of Hersh's wild Osama bin Laden conspiracy theory

Renowned journalist Seymour Hersh has a startling article claiming the White House lied about how it killed Osama bin Laden, and a former CIA official told us Monday the story is just "not plausible."

"Bits and pieces you could say are plausible, but when you put the whole conspiracy theory together, no, it is not plausible," Robert Grenier, the CIA's former top counterterrorism official, told Business Insider. "It simply isn't the way that government works."

In an investigative piece in the London Review of Books, Hersh offers an alternate history of the events surrounding the former al-Qaeda leader's death, based primarily on the account of an individual that Hersh identifies as a retired CIA source.

Hersh disputes the official White House story that bin Laden was hiding out when he was killed in Pakistan, and that US officials only alerted Pakistani officials of his death after the fact. In fact, Hersh claims, Pakistani officials had held bin Laden since 2006 and eventually helped the US take him down.

Grenier acknowledged that Hersh has an impressive record of important stories. Indeed, Hersh won wide acclaim for his reporting on the My Lai massacre, a horrific mass killing of unarmed civilians in Vietnam. However, some experts have called the seasoned reporter's recent stories into question.

"Sy Hersh has obviously broken some major stories in the past. No one can take that away from him," Grenier said. "But a story like this is wild, not credible, and thinly sourced. It just strikes me as irresponsible."

Hersh's assertion that the US government pressured the Pakistanis to turn over bin Laden does not line up with how foreign aid works, according to Grenier.

"The US government uses assistance as a tool to encourage or discourage different behaviors, but the idea that you could calibrate this - you could turn the spigot slightly - it just doesn't work that way," Grenier said. "It's a much cruder tool."

While it was possible that a single source could have access to the information that Hersh describes, the source would need to be high up in the CIA, according to Grenier. But that's unlikely, he said.

"If [deputy CIA director] Michael Morell were the source, then yeah, it's quite possible," Grenier said. "I guess that would add another twist to the conspiracy that he's coming out and denouncing the whole thing."

Morell, for his part, also denounced Hersh's reporting. In an interview with CBS News, the former deputy director said that report was almost entirely false.

"It's all wrong," former CIA deputy director Mike Morell said. "I started reading the article last night and I got a third of the way through because every sentence I was reading was wrong."