The story was first published in the April 1952 issue of “Thrilling Wonder Stories.”
Synopsis on the back cover:
“From a past master of science fiction comes this jet-paced account of the adventures of Federal Agent George Helmfleet Jones. Combining sleuthing genius with the scientific advances of an advanced age, Jones tackles a series of sinister crimes – crimes made more sinister still because the perpetrators also combine genius with astonishing scientific discoveries.
“In the beginning, Jones is assigned to locate an illegal production source of perizone, the closely controlled new drug that cures every type of blood disease. His trail leads him to an upstate New York research institute where an odd collection of experts is engaged in secret experiments under the strictest security measures. But security in Jones’ time is not the security known to the 1950’s – recent laws have kept the government from probing into individual affairs under threat of prosecution. This is hampering enough to an investigator on an important case, but then Jones runs into a half dollar that is perfect in every way – except that everything on it is reversed; an immensely valuable stolen statue – which can’t be stolen because it’s still on display; and the identical twin of a beautiful scientist – who doesn’t have a sister!
“These all but incredible mysteries bring Jones to a master coup that just can’t happen and yet does: three million dollars have been sent in a sealed rocket from New York to San Francisco; there is no pilot on the unmanned ship, which does not stop anywhere in transit – but when the hold is open, the money has unaccountably vanished! Jones, discovering a startling connection between the two impossible cases, puts his own life in double jeopardy – he has to close in on a killer who can be in two places at the same time!”
[Note: This story is available for reading in the Internet Archive:
archive.org/details/Thrilling_Wonder_Stories_v40n01_1952-... ]