Mihaila Street 1, Daugavpils, LV-5401, Latvia
On June 26, 1941, German troops occupied Daugavpils.
Colonel General of the German Army Heinz Guderian noted in his memoirs that on June 26, the 8th Tank Division of Army Group "North" managed to capture Dvinsk (Daugavpils) and seize the bridges over the Western Dvina River in this area.
In July 1941, the Nazis organized a large prisoner of war camp also in Daugavpils – Stalag-347. In August, the camp was renumbered to Stalag-340. Initially, prisoners were held in the powder magazines of the Dinaburg fortress, and later in vegetable warehouses and stables behind the ramparts on its northern side. A poster with an image of a stick and the inscription "Here is your master!" hung on the camp gates. Below it, on a blackboard, the date was recorded daily along with the number of prisoners held in the camp.

In the autumn, as the number of prisoners increased, they began to be held outdoors within the fortress grounds. Vera Efimova, a hospital worker for prisoners, recounted that behind the fence "at every step there were bodies of prisoners killed by clubs or rifle butts... Unimaginably monstrous acts took place here...". Part of the harsh winter was spent by prisoners in dugouts they had made themselves, which offered no protection from the cold or snow.

Only later were the prisoners transferred to barracks built on the fortress esplanade. Here, a central camp was organized. Its branches were located in the former depot at the Daugavpils-2 station, in old stables on Aglonas and Viljanu streets, in Vidus, in the buildings of a pottery factory, and other places.
The security of Stalag-340 was very well thought out, making escape from the camp practically impossible. Escapes occurred only during work outside the camp, and some were successful.

Mass shootings took place in the camp. They shot the weak, prisoners in line near the kitchen when soup rations were insufficient, and killed anyone who fell ill with typhus in the barracks. Beatings and corporal punishments were a daily occurrence. The camp had a special fenced field – a place for punishments. Sometimes up to 40 people were brought there and beaten with rubber batons for the slightest "disobedience". Stalag-340 also had its own hospital. Many survivors owed their lives to a fellow prisoner, surgeon A. Gibradze. Working in the camp infirmary, he eased the suffering of the wounded and also delayed reporting deaths, thereby allowing prisoners to receive extra rations for 3-4 days and support the most weakened. Secret meetings to organize escapes were also held in his "operating room".
The extermination of prisoners in the camp happened even faster than in Riga. Vera Efimova, who worked in the hospital, showed: "Prisoners were treated with some mixture they were given to drink, as well as an ointment for burns. Wounds from these mixtures never healed. Few left this hospital alive. Near the hospital, five burial teams of prisoners worked, transporting the dead to the cemetery. Sometimes a living person was placed in the cart, covered with 6-7 dead or shot prisoners. The living were buried with the dead; patients tormented by nightmares were beaten with sticks in the hospital." It seems that in Daugavpils, living people were very often buried together with the dead. Witnesses claim this. Daugavpils resident E. Krylova recounted: "It was not uncommon for 6 or more prisoners weakened by hunger to be taken in carts to the cemetery and left there overnight. If they did not die, they were buried alive." A medical commission that conducted exhumations of the graves often found asphyxiation — cessation of breathing due to lack of oxygen.
From September to October 1942, the famous Tatar poet Musa Jalil, future author of the "Moabit Notebooks," was a prisoner of the Stalag-340 concentration camp. In the Daugavpils fortress, he was imprisoned on September 2 in one of the warehouses (half barracks, half dugout). Under his padded jacket, he kept a hidden notebook and a thick brown notebook. Only his friend Salikh Ganiev knew about this. And in the sleeve of his jacket, he kept the tip of a pencil. Jalil wrote secretly in Daugavpils. Before being sent further, Musa Jalil handed the notebook with poems to his fellow countryman Garif Khafizov with the request: if you survive, send it to Kazan, to any newspaper or magazine editorial office. On October 15, 1942, Musa Jalil, Salikh Ganiev, Zinnat Khasanov, and many others were taken out of Daugavpils. About a month later, searches began in the barracks of the Daugavpils fortress. Khafizov did not manage to hide the notebook – it was torn from his hands and thrown into the stove. When the fire died down, only three pages remained, including the poem "If I Were a Swallow" ("If Only I Were Free"). While imprisoned in Polish and German prisons, Musa Jalil restored the poems from memory, as he knew them by heart (according to available information).
Today, a memorial plaque is installed at the presumed place of his imprisonment.

It bears the poet's words: "I always dedicated my songs to the Motherland, now I give my life to the Motherland..."
The conditions for prisoners were terrible: the premises were unheated, rotten roofs did not protect from rain. Prisoners were starved, subjected to torture and abuse, sent to unbearable labor, and mass shootings were carried out. Epidemics raged in the camp. In the winter of 1942-1943, during a typhus epidemic, mortality in the camp reached up to 900 people per day.
Latgale Gebietskommissar Schwung wrote in an October 1941 report that about 100,000 prisoners of war were held in the Rezekne and Daugavpils camps combined. Comparing the sizes of the two camps, we can conclude that the majority of prisoners were in Daugavpils. In January and February 1942, the "Pomeranian Commission" selected the strongest prisoners and transported them to Germany. Schwung's comment on this action is notable: "The removal of prisoners of war from our district," Schwung wrote on February 10, 1942, "those whom the Pomeranian Commission delivered to Germany was primarily a political event. This slowed the formation of a new communist cell." According to the occupiers' statistics, due to the terrible dying out of prisoners primarily from hunger and typhus epidemics during the first winter of the war and the deportation of prisoners to Germany in summer 1942, only 15,595 prisoners remained in the Daugavpils camp, with 886 prisoners working outside the camp in agricultural labor. Mortality in Daugavpils was truly horrific. A mass grave on the fortress rampart near the crossing at the 214 km mark contains 45,000 prisoners of war. In Pogulyanka – in the sands near Budrevich's dacha – about 50,000, at the Garrison Cemetery – 26,000. Small graves were found near the Daugavpils-2 passenger station, at the "Bridge" railway station at 267 km, on Ventspils Street near the Tanaev house. In total, the number of dead is about 124,000. The commandant of Stalag-340, Major Hefner, his assistant Captain Hugo Meyer, and Captain Nisin, who later replaced Meyer, are responsible for many deaths of thousands of tortured prisoners of war. Meyer was especially brutal. If he did not like the appearance of a prisoner, he would beat the unfortunate man. When Meyer rode a bicycle around the camp, prisoners were ordered to move 10 meters aside. Those who did not manage or were unable to do so paid with their lives. Officers of the camp administration such as Paulin, Laupert, Marten, kitchen manager Roan, statistician Boldi, and others were distinguished by sadistic cruelty.
From November 26 to December 1, 1944, a commission investigating fascist atrocities worked in the Pogulyanka forest and fortress. It exhumed the remains of those killed in mass shootings and established that the prisoner of war camp lacked even the most basic conditions for sustaining human life, which was a gross violation of the Hague and Geneva Conventions on prisoners of war.
Sources:
https://www.sgvavia.ru/forum/150-605-1
https://dzen.ru/a/XpBMf3UDbyCyRHxR
http://dinaburgascietoksnis.lcb.lv/stalagaRU.html
https://dzen.ru/a/Y-yFAwvIUVUMrNuu
https://gorod.lv/novosti/265917-den-v-istorii-muse-dzhalilu-110-latviiskii-sled-v-zhizni-geroya-poeta#ixzz8j4uky0Uu