Szmalcownik (Polish pronunciation: [ʂmalˈtsɔvɲik]), in English also spelled shmaltsovnik, is a pejorative Polish slang expression that was used during World War II for a person who blackmailed Jews who were in hiding, or who blackmailed Poles who protected Jews during the German occupation.
The term originated in the German word Schmalz (Polish phonetic spelling: szmalc, literally meaning "lard") and indicated the blackmailer's financial motive.
The Polish Secret State considered szmalcownictwo an act of collaboration with the occupying Germans. The Home Army (Armia Krajowa) punished it with death as a criminal act of treason. Blackmailers were sentenced to death by Polish Underground Special Courts for crimes perpetrated against Polish citizens. A decree of 31 August 1944 of Polski Komitet Wyzwolenia Narodowego (the Polish Committee of National Liberation) also condemned such acts as collaboration with Germany. This decree remains valid law in Poland, and anyone convicted of szmalcownictwo during the war may face life imprisonment.
Gunnar S. Paulsson estimates that the total number of szmalcowniks in Warsaw were "as high as 3-4 thousand." The damage that these criminals did was substantial. Most were interested in money. By stripping Jews of assets needed for food and bribes, harassing rescuers, raising the overall level of insecurity, and forcing hidden Jews to seek out safer accommodation, blackmailers added significantly to the danger Jews faced and increased their chances of getting caught and killed. At the beginning of the German occupation, szmalcowniks were satisfied with a few hundred zlotys in extortion, but after the death penalty was introduced for hiding Jews, the sums rose to several hundred thousand zlotych.
The Germans sometimes also treated szmalcowniks as criminals and punished them. The reason was that szmalcowniks also bribed German officials and police: after a rich Jew had been denounced, the szmalcownik and corrupt German shared the loot.
On December 29, 1942, the Council for Aid to Jews ("Żegota") appealed to the Government Delegate for the country for a declaration on szmalcownicy . On March 18, 1943, the Civil War Command subordinated to the Government of the Republic of Poland in exile announced:
"Every Pole who interacts with their murderous action whether by blackmailing or denouncing Jews, whether exploiting their cruel position or participating in looting, commits a grave crime against the rights of the Republic of Poland and will be punished immediately ..." 
A warning of the Civil Resistance Directorate that cases of blackmailing Jews who hide and help Poles are registered and punished published in the underground press . The Armia Krajowa Information Bulletin also published its own article entitled Hyenas and in April 1943 another warning against blackmailers . In order to stop the wave of blackmail "Żegota" as soon as possible, they made a proposal to make fictitious judgments, but it was rejected by the Government Delegation for Poland .
The announcement of the prosecution and punishment of blackmailers was included in the communiqué about the founding of the Underground Fighting Direction, signed by the Government Delegate and the Home Army Commander of the Home Army . "Żegota" spent three times (in May, August and September 1943) in a circulation of 25,000 copies of leaflets signed by Polish Independence Organizations stigmatizing blackmail and szmalcownictwo and appealing to Polish society to help Jews  .
Szmalcownicy began to be sentenced to death by special civil courts in Warsaw and Krakow . Many of them were also confidants of the German authorities . The first sentences of the Warsaw szmalcowniki were carried out earlier, in May and June 1943, as part of the so-called "C" campaign aimed at eliminating confidants, szmalcowniki and agents collaborating with the German apparatus of repression . For this activity death sentences by shooting were made, among others on two navy police officers from the 13th police station, who dealt with blackmailing Poles hiding Jews .
On July 5, 1943, two soldiers of the People's Guard Jan Andrysiak and Roman Rycerz liquidated the blackmailer who issued escapees from the ghetto, the Wolf family hiding in the apartment at ul. Łomiańskiej . On August 25, AK "Podkowa" unit executed the verdict on szmalcownik Bogusław Pilnik, who was also a Gestapo informer . In Krakow, one of the first convictions was executed on July 17, 1943, on Jan Grabec .
The intensification of actions against szmalcownikom took place in the autumn of 1943 and in the winter of 1943/1944 . In Warsaw, on October 28, a unit of Kedywu OW AK shot plutonium from 1 Criminal Investigation Bolesław Szostak . On November 5, 1943, in the cafe "Swann" at Nowy Swiat, the combat patrol DB "3" shot Tadeusz Stefan Karcz . Two successive blackmailers, corporal navy police officer Antoni Pietrzak and Jan Żmirkowski, the Gestapo secretary, and the Home Army killed in early 1944 . On February 24, 1944, a death sentence was executed on Jan Łakiński, who could also be responsible for the denunciation of the "Krysia" bunker . According to Dariusz Libionka in Warsaw, until the outbreak of the Warsaw Uprising death sentences were passed on a dozen szmalcownikach .
However, the judgments of the underground court had little effect on the enormous number of blackmail and denunciation . According to Władysław Bartoszewski, the number of death sentences issued against szmalcownicy by the courts of the Polish Underground was significant, but because of the difficulty in tracing them, these activities could not effectively deter those criminals .
Szmalcownictwo for a crime was also recognized in the People's Republic of Poland. Article 1 point 2 of the PKWN decree of August 31, 1944 on punishments for fascist Nazi criminals guilty of murder and abuse of civilians and prisoners, and for traitors to the Polish nation, issuing to Germans people sought by them was persecuted as a crime punishable by death and judged in lawsuits called (from the date of the decree) in the so-called "sierpniówkach" . To extort money from such persons (article 2) was punished by imprisonment under 15 years or by life imprisonment. Those blackmailers whose sacrifices did not lose their lives took over the 1956 amnesty .
- Jan, Grabowski (2004). "Ja tego żyda znam!": szantażowanie żydów w Warszawie, 1939–1943 / "I know this Jew!": Blackmailing of the Jews in Warsaw 1939-1945 (in Polish). Warsaw, Poland: Wydawn. IFiS PAN : Centrum Badań nad Zagładą Żydów. ISBN 83-7388-058-5. OCLC 60174481.
- Źródło: Żydzi polscy, zeszyt 24, "Sprawiedliwi wśród narodów" str. 11 artykuł "Śmierć dla szmalcowników" dodatek do Rzeczpospolitej z 23 września 2008
- Biuletyn IPN 3 (12)/2013, p. 5, Instytut Pamięci Narodowej