The bill was handed to Joseph Yun, former Special Representative of the Ministry of Foreign Affairs of North Korea, who traveled to Pyongyang in June 2017 to bring warm beer home, the sources said, CNN.
Yun, who was ordered by President Donald Trump to bring Warmbier home, signed the bill after informing then-Foreign Minister Rex Tillerson. Tillerson then told Trump about the bill, according to the source.
The Trump administration has not paid this bill, a third source familiar with the affair told CNN on Thursday, adding that North Korea had not addressed the problem as it sought to mitigate tensions with the US in 2018, or as Secretary of State Mike Pompeo negotiated the release of three Americans in the same year, the source said.
"We made it clear that they would never get anything" when the negotiations for the release of the 3 Americans took place.
Earlier this month, Pompeo dropped the idea of a US ransom for hostages at an event attended by Otto Warmbier's family.
"Please remember that any money to a terrorist or terrorist regime brings money so they can take more of our people," he said. "We can not accept this risk, they would not ask that from us."
While the North Koreans did not raise the issue during Trump's summit meeting with Kim Jong Un in Singapore and Vietnam, the source noted that the expectation of this payment could be increased again.
This is especially the case because the Foreign Ministry in North Korea is gaining in influence at the negotiating table, and it is they who handed Yun this bill, the source said.
Yun, who was reached by CNN on Thursday, said he could not confirm the report because of the delicate discussion.
"I can not confirm that," Yun said. "These are diplomatic talks and negotiations that I do not confirm."
"We do not comment on hostage negotiations for why they were so successful during this administration," White House Press Secretary Sarah Sanders said in a written response to CNN.
The State Department declined to comment and referred to the Sanders response.
Warmbier was arrested by North Korean officials in January 2016 when he tried to return from a tour of the country to the United States. He was returned to his family "with severe brain damage and in an unresponsive state" on June 13, 2017, and died six days later.
Fred Warmbier, Otto's father, told The Washington Post he was unaware of the bill, but described it as a "ransom" for his deceased son.
"He tells me he did not know about it and I'll take him to his word," Trump said during a press conference, also claiming that Kim "felt very bad, but he knew the case very well, but he knew it later. "
These comments caused the Warmbier family to blame.
"We were respectful during this summit meeting, and now we have to speak out: Kim and his evil regime are responsible for the death of our son Otto Kim and his evil regime are responsible for unimaginable cruelty and inhumanity. Change that. Thank you." Fred and Cindy Warmbier, Otto's parents, said in a statement provided to CNN.
Trump later addressed the topic on Twitter, arguing that he was "misinterpreted" after he successfully brought Warmbier out of North Korea and claimed to hold the country responsible for Warmbier's death – though he did not mention Kim's role.
"I never like being misinterpreted, especially when it comes to Otto Warmbier and his big family," said the then-president. "Remember, I got Otto out with three others, the previous government did nothing, and he was put on their clock."
CNN's Devin Cole, Abby Phillip and Jennifer Hansler have contributed to this report.