Jack-in-the-Box

"Again Sir Clinton Driffield, an old favorite with Connington fans, gets into action with all his usual acumen, and the unraveling of another mystery proceeds under his suave direction to its inevitable outcome.
"Jack-in-the-Box opens with the discovery of a Viking's hoard of gold, stolen many centuries ago from a Norman abbey and accidentally unearthed during an archaeologist's excavations on the site of a Roman camp. A local legend prophesies death to anyone who touches it. Soon after, the archaeologist dies in an air raid, and at the same time some of the gold vanishes from his house.
Living in the neighborhood is a mulatto who professes to have discovered a 'New Force' capable of killing at long distances. To convince a skeptical doctor, some wild rabbits are killed by an agency which leaves no trace of poison or injury on their bodies. Later, a ne'er-do-well dies in a similar manner, and the missing gold is found buried in his garden. A chronic alcoholic is found dead from gas poisoning, another victim dies like the rabbits, and, finally, a girl disappears.
"Mr. Connington once more justifies his considerable reputation for skillful plotting and for ingenuity in working out his solution."
Jack-in-the-Box was published in 1944.