Question: What is the name of this series of mass executions during World War II, which, along with Sambor Ghetto, was anenexed to the Ukranian SSR?

<P0-S0> The NKVD prisoner massacres were a series of mass executions carried out by the Soviet NKVD secret police during World War II against political prisoners across Eastern Europe, primarily Poland, Ukraine, the Baltic states, Bessarabia and other parts of the Soviet Union from which the Red Army was retreating following the Nazi German attack on the Soviet positions in occupied Poland, known as Operation Barbarossa. <SEP> <P1-S0> Stanisławów Ghetto (Polish: "getto w Stanisławowie" , German: "Ghetto Stanislau" ) was a Jewish World War II ghetto established in 1941 by the "Schutzstaffel" ("SS") in the prewar Polish city of Stanisławów in the south-eastern region of Kresy (now Ivano-Frankivsk, Ukraine) occupied by Germany after Operation Barbarossa. <P1-S1>  Before the joint Nazi-Soviet invasion of Poland in 1939 Stanisławów was the capital of the Stanisławów Voivodeship in the Second Polish Republic. <P1-S2>  The Soviets annexed the city to the Ukrainian SSR in 1939 along with the entire region, but renamed it as Ivano-Frankivsk in 1962, long after the war ended. <P1-S3>  In 1941 Stanisławów (then, Stanyslaviv) was overrun again, this time by the Wehrmacht army, in the course of the German attack on the Russian positions behind the Curzon Line (see map, marked in red), and incorporated it into their own "Distrikt Galizien", as the fifth district of the "Generalgouvernement". <SEP> <P2-S0> Sambor Ghetto (Polish: "getto w Samborze" ) was a Jewish World War II ghetto established in March 1942 by the "Schutzstaffel" ("SS") in the prewar Polish city of Sambor in the south-eastern region of Kresy (now Sambir, Ukraine). <P2-S1>  Sambor was occupied by Nazi Germany twice, first during the joint German-Soviet invasion of Poland in 1939, and again, after the 1941 Operation Barbarossa. <P2-S2>  Before the war, Sambor was a county seat in the Lwów Voivodeship of the Second Polish Republic. <P2-S3>  The invading Germans handed the town over to the Soviets in accordance with the Nazi-Soviet Pact against Poland. <P2-S4>  Sambor was annexed to the Ukrainian SSR along with the entire region in the atmosphere of intimidation, and the NKVD terror. <P2-S5>  In 1941 the city was overrun again by the Wehrmacht army in the course of the German attack on the Soviet positions behind the Curzon Line (see map, marked in red), and incorporated it into their own "Distrikt Galizien". <P2-S6>  According to the Polish census of 1931 Jews constituted nearly 29 percent of the town's inhabitants, most of whom were killed during the Holocaust. <P2-S7>  Sambor (Sambir) is not to be confused with the much smaller Old Sambor (Stary Sambor, now Staryi Sambir) located close-by, although their Jewish history is inextricably linked together. <SEP> <P3-S0> The massacres in Piaśnica were a set of mass executions carried out by Nazi Germany during World War II, between the fall of 1939 and spring of 1940 in Piaśnica Wielka (Groß Piasnitz) in the Darzlubska Wilderness near Wejherowo. <P3-S1>  The exact number of people murdered is unknown, but estimates range between 12,000 and 14,000 victims. <P3-S2>  Most of them were Polish intellectuals from Gdańsk Pomerania, but Poles, Jews, Czechs and German inmates from mental hospitals from General Government and the Third Reich were also murdered. <P3-S3>  After the Stutthof concentration camp, Piaśnica was the largest site of killings of Polish civilians in Pomerania by the Germans, and for this reason is sometimes referred to as the "second" or "Pomeranian" Katyn. <P3-S4>  It was the first large scale Nazi atrocity in occupied Poland.