Updated

Ronald Reagan's son said Tuesday that the online auction of a vial purportedly containing the late president's dried blood is "bogus" and demanded the auction be canceled.

"It's so bogus that whoever is doing it is lying to everybody," Michael Reagan told FoxNews.com.

The item went up for sale on the website of PFC Auctions, and by Tuesday morning the bid was approaching $12,000. The auction is set to run until Thursday -- but Michael Reagan as well as The Ronald Reagan Presidential Foundation have raised objections.

"If indeed this story is true, it's a craven act and we will use every legal means to stop its sale or purchase," foundation director John Heubusch said in a written statement.

The auction site claims the vial was originally obtained by a woman working at a lab in Columbia, Md., in 1981, at the time Reagan was shot by John Hinckley Jr. "Her lab did the bloodwork and testing for President Reagan," the site says.

The woman, who died in 2010, kept the vial -- and her son is now trying to sell it.

But Michael Reagan disputed the entire story. He said there wouldn't have been a need, for instance, to check his blood type -- since that would have already been known. And he noted there wouldn't have been blood on the scene either. "My father was bleeding internally, not externally," Reagan said.

"This is somebody just trying to make money ... trying to make money off Reagan," he said.

The foundation, separately, is trying to find out how the vial -- if it's legitimate -- ever left the lab in the first place. Heubusch said the foundation has "spoken to GW Hospital and are assured an investigation as to how something like this could possibly happen is underway. Any individual, including a president of the United States, should feel confident that once they enter into the care of a medical system their privacy and rights are held inviolable."

The lab was supposedly contracted for bloodwork by George Washington University Hospital as well as Walter Reed medical center after the shooting.

The "letter of provenance" from the son posted online detailed his efforts to contact the Ronald Reagan Presidential Foundation & Library and other authorities about the sale. The seller claimed a Reagan library official initially said he wanted him to donate the vial.

"I told him that I didn't think that was something that I was going to consider," he wrote. "... I was a real fan of Reaganomics and felt that President Reagan himself would rather see me sell it rather than donating it."

He also claimed the library consulted other agencies like the National Archives and FBI and that they determined "everything was OK." And he claimed that when his mother originally took the vial home, the lab director "told her no problem."

The auction site describes the item as a 5-inch glass vial with a green rubber stopper, containing a "quarter-inch ring of blood residue at the end of the inserted rubber stopper."

PFC Auctions told Sky News that they had not heard from The Reagan Foundation.