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Former Vice President Joe Biden said Sunday that the Navy's decision to remove the captain who sounded the alarm on coronavirus cases aboard his ship is "close to criminal."

"I think it's close to criminal the way they're dealing with this guy," Biden said on ABC News' "This Week." "Not his conduct. The idea that this man stood up and said what had to be said, got it out that his troops, his — his Navy personnel were in danger — in danger."

"Look at how many have the virus," he said, adding, "I think the guy should ... have a commendation rather than be fired."

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The Navy announced Thursday that it had relieved Capt. Brett Crozier of his post commanding the USS Theodore Roosevelt, an aircraft carrier with a crew of nearly 5,000. Crozier will keep his rank and remain in the Navy.

Crozier had sent a strongly worded letter to Navy leadership earlier in the week detailing his concerns about how COVID-19 was spreading on his ship. The letter was leaked to the media.

Acting Navy Secretary Thomas Modly said at a news conference Thursday that Crozier was removed for breaking the chain of command, sending his letter over "nonsecure unclassified email" to a "broad array of people."

"I have no doubt in my mind that Captain Crozier did what he thought was in the best interest of the safety and well-being of his crew," Modly said. "Unfortunately, it did the opposite. It unnecessarily raised the alarm of the families of our sailors and Marines with no plans to address those concerns."

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Modly, who said the decision was his alone, said Crozier "allowed the complexity of the challenge of the COVID breakout on the ship to overwhelm his ability to act professionally."

The ship, which was operating in the Pacific, pulled into port in Guam last month after multiple crew members tested positive for the virus. The number of infected rose to 93 by Wednesday, and more than 1,000 people were taken off the ship and placed into isolation on Guam.

Asked Saturday about Crozier's removal, President Donald Trump said he didn't "know much about it" before tearing into the captain for writing his letter.

"The letter was a five-page letter from a captain, and the letter was all over the place," Trump said. "That's not appropriate. I don't think that's appropriate. And these are tough people. These are tough, strong people. I thought it looked terrible, to be honest with you.

"Now, they made their decision. I didn't make the decision. Secretary of defense was involved, and a lot of people were involved," Trump continued. "I thought it was terrible what he did, to write a letter? I mean, this isn't a class on literature. This is a captain of a massive ship that's nuclear powered, and he shouldn't be talking that way in a letter."

As Crozier was leaving his ship following his removal, a crowd of applauding sailors was seen on video cheering his name and waving goodbye.

Defense Secretary Mark Esper defended Modly on Sunday, saying that he "made a tough decision, a tough call."

"I have full faith and confidence in him and the Navy leadership, and I supported their decision," he said.

Asked about a Washington Post report that the White House directed the Navy to remove Crozier, Esper said the call was Modly's alone.

"This is a chain-of-command issue," Esper said. 'It's an issue of trust and confidence in the captain of the ship."

Speaking on CNN's "State of the Union," Esper also said, "We need to take care of the sailors on the ship."

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"We need to ensure their well-being and get that ship back out to sea as soon as possible," he said. "I'm pleased to report, right now, over half of the ship has been tested. Only 155 sailors have come up positive. Those are all mild and moderate. There have been no hospitalizations whatsoever."

Esper said that while there is "an investigation ongoing" into Crozier, there "is not a need, necessarily, to remove every sailor from the ship."

"You actually cannot do that, because there's nuclear reactors to be run," he said. "You have very sensitive equipment. You have weapons onboard that ship, so you cannot completely evacuate the ship."