At 17.11 hours on 19 July 1942 U-332 began shelling the unescorted Leonidas M. (Master Elias Halkias) after missing her with a spread of two torpedoes 15 minutes earlier about 600 miles south of Cape Race. The U-boat ceased fire when the crew abandoned ship after sending distress signals. A first coup de grâce fired at 17.25 hours missed, but at 17.42 hours a second was fired from the stern torpedo tube and struck in the forward part of the ship, causing her to break in two and sink within 25 seconds. The Germans questioned the survivors and took the master and chief engineer as prisoner aboard. When U-332 left the area, another steamer was sighted that headed towards the lifeboats and picked up the survivors about three hours after the attack. This proved to be the Portuguese steam merchant San Miguel which was stopped for contraband control at 21.27 hours. She was released after a boarding party inspected the ship and landed the survivors at Baltimore on 25 July.

USS Rhind (DD 404) (Cdr O.W. Spahr, Jr., USN) was detached from the destroyer screen of USS Washington (BB 56) after receiving the distress signals from Leonidas M. and arrived in the area about 20 hours after the attack, but only found one empty lifeboat, five rafts and considerable wreckage in position 36°55N/51°55W.