Ampumisen syynä pidetään Neuvostoliiton halu saada haltuunsa Ranskalaista diplomaattipostia.
Tapahtuma oli dramaattisimpia tapahtumia välirauhan ajan Suomessa ja laittoi liikkeelle kosolti huhuja Baltian maiden miehityksen kiristämässä ilmapiirissä.
Kalevan ohjaamossa oli kahden hengen miehistö: ohjaaja kapteeni Bo von Willebrand ja radisti Tauno Launis. He olivat lentäneet Kalevan samana päivänä normaalilla päivittäisellä vuorolennolla Tukholmasta Turun ja Helsingin kautta Tallinnaan. Iltapäivällä Kalevan oli tarkoitus palata samaa reittiä takaisin Tukholmaan.
Virolais-Suomalaissyntyinen Gunvor Maria Luts
Ruotsalainen Max Hettinger
Saksalainen liikemies Friedrich Offermann
Saksalainen liikemies Rudolf Cöllen
Ranskalaiset kuriiri Paul Longuet
Ranskalainen kuriiri Frederic Marty
Yhdysvaltalainen kuriiri, Yhdysvaltain Helsingin-suurlähetystössä työskennellyt Henry William Antheil, säveltäjä George Antheilin veli.
Kolmella kuriirilla oli mukanaan yhteensä 227 kiloa diplomaattipostia.
Kaksi neuvostoliittolaista DB-3T-pommikonetta odotti Kalevaa Suomenlahden yllä kahden kilometrin korkeudessa. Toinen niistä ampui varoituslaukauksia, mutta Kaleva jatkoi matkaansa. Lähellä Kerin majakkasaarta toisen pommikoneen konekivääriampuja avasi tulen noin 50 metrin etäisyydeltä. Kaleva sai osumia vasempaan moottoriinsa, joka syttyi palamaan. Kaleva kääntyi vasemmalle kyljelleen ja syöksyi mereen Kerin majakkasaaren pohjoispuolelle, noin 30 kilometrin päähän Tallinnasta.
Kalevan putoamispaikalla veden syvyys on noin 100 metriä. Kaikki yhdeksän Kalevassa ollutta ihmistä saivat surmansa. Heidän ruumiitaan ei löydetty.
Tante Junkers Ju-52 / Aunt Junkers Ju-52
Kaleva, registered OH-ALL, was a civilian Junkers Ju 52 passenger and transport plane, belonging to the Finnish carrier Aero O/Y. The aircraft was shot down by two Soviet Ilyushin DB-3 bombers during peacetime between the Soviet Union and Finland on June 14, 1940, while en route from Tallinn to Helsinki, killing all 9 on board
A few minutes after taking off in Tallinn, Kaleva was joined at close range by two Soviet DB-3T torpedo bombers. The bombers opened fire with their machine guns and badly damaged Kaleva, making it crash into the water a few kilometers northeast of Keri Lighthouse. All nine passengers and crew members on board were killed.
Estonian fishermen had witnessed the attack and crash of the plane. Shortly after the crash the Soviet submarine Shch-301 (Щ-301) surfaced and inspected the fishing boats. After confiscating items taken from the wreck by the fishermen, the Soviets picked up diplomatic mail from the wreck and the sea. The future top-scoring Finnish pilot Ilmari Juutilainen was sent to inspect the crash site. After the Soviets spotted the Finnish airplane, the submarine hid its flag.
At the time of the incident Finland was not at war with the Soviet Union. The attack was probably part of the Soviet preparations for the full-scale occupation of Estonia, which took place two days after the Kaleva incident, on 16 June 1940. The occupation was preceded for several days by a Soviet air and naval blockade, which included preventing diplomatic mail from being sent abroad from Estonia.
The passengers on the last flight of Kaleva included two German businessmen, two French embassy couriers, one Swede, an American courier, and an Estonian woman. The French couriers had over 120 kilograms of diplomatic mail in the plane.
The American courier was reportedly transporting the U.S. military codes to safety from Estonia.
The plane was piloted by Captain Bo von Willebrand, and Tauno Launis was the wireless operator. The American victim was Henry W. Antheil, Jr., younger brother of noted composer George Antheil.
Antheil worked as a clerk at the U.S. Legation in Helsinki. In 2007, he was honored for his service in a ceremony at the U.S. Department of State. His name was inscribed on the U.S. Department of State's Wall of Honor.
The Government of Finland did not send any complaints or questions to the Soviets out of fear of hostile Soviet response, and the true reason for the crash was hidden from the public. This was due to the heavy pressure put upon Finland during the Interim Peace by the Soviets. After the outbreak of the Continuation War, the incident was described in detail by the government.
The commander of Shch-301 G. Golderg's report on the incident held in the Russian State Naval Archives starts with the notice of a Finnish airplane on its way from Tallinn to Helsinki on June 14, 1940 at 15.05 PM. According to the report, the airplane was chased by two Soviet Tupolev SB high-speed bombers. At 15.06 PM, the Finnish airplane caught fire and fell into the sea, 5.8 miles from the submarine.
At 15.09 PM the submarine took course to the crash site and made it to the location by 15.47 PM. The submarine was met by 3 Estonian fishing boats near the detritus of the airplane. The Estonian fishermen were searched by lieutenants Aladzhanov, Krainov and Shevtshenko. All valuables found from the fishermen and in the sea were brought on board of the submarine: the items included about 100 kg. of diplomatic post, valuables and foreign currencies.
At 15.58 a Finnish fighter plane was noticed with the course towards the submarine. The airplane made 3 circles above the site and then flew towards Helsinki. The exact coordinates of the crash site were determined to be at 59°47′1″N 25°01′6″E.
Captain A. Matvejev's report states that on board the Shch-301 noticed an airplane crash on June 14, 1940 at 15.06 on 5.8 miles distance from the submarine. At the crash site 3 Estonian fishing boats and the remains of the airplane were found. At 15.58 PM a Finnish fighter plane made 3 circles above the crash site. By 16.10 PM all items found from the sea and from the hands of the fishermen were brought on board the submarine.
The items included about 100 kg of diplomatic mail, and valuables and currencies including: 1) 2 golden medals, 2) 2000 Finnish marks, 3) 10.000 Romanian leus, 4)13.500 French francs, 5) 100 Yugoslav dinars, 6) 90 Italian liras, 7) 75 US dollars, 8) 521 Soviet rubles, 9) 10 Estonian kroons. All items were put on board of patrol boat "Sneg" and sent to Kronstadt.