The gang that kidnapped, tortured and killed a young Parisian Jew had also threatened several prominent businessmen, lawyers and a well-known humanitarian activist, a French newspaper reported Saturday. The daily Liberation reported that the group behind the killing, which authorities have linked to anti-Semitism, tried to extort money from a founder of Medecins Sans Frontieres, or Doctors Without Borders. Also targeted were the director of the Arte TV channel, a Paris lawyer and the head of a supermarket chain, the newspaper reported, citing police officials. Police investigating the killing earlier this month of 23-year-old Ilan Halimi have made several arrests. The brutal killing has revived concerns of anti-Semitism in France. A march against racism and anti-Semitism, with numerous public figures, including government ministers, was planned for Sunday. On Thursday, President Jacques Chirac attended a memorial ceremony for Halimi at the Paris synagogue. Halimi, a cell phone salesman, was kidnapped Jan. 21, and his family later received ransom demands, starting with one for around $537,000. The young man was found naked, handcuffed and covered with burn marks on Feb. 13 near railroad tracks south of Paris. He died on his way to a hospital. Rony Brauman, a founder of the humanitarian group Medecins Sans Frontieres, and who is of Jewish origin, confirmed on LCI television that he had been the object of an extortion attempt in 2004. However, Brauman said he did not believe anti-Semitism played a role in his case and those of others who were threatened for money in the same period. "The question of being Jewish or not had no incidence. ... It was pure extortion," he said on LCI. He said that in April 2004 he received a letter demanding some $350,000 or his life. Liberation quoted him as saying that the letter contained a photograph of armed, hooded men in front of Brauman's home, south of Paris. Several months later, two Molotov cocktails exploded in the courtyard of his home and a gunshot was fired at his door, he told LCI. Arte director Jerome Clement said on France 2 TV that he received a video cassette showing hooded men firing bazookas and machine guns and saying, "Look what will happen to you if you don't pay the ransom." Interior Minister Nicolas Sarkozy said Tuesday that Halimi's attackers were primarily motivated by greed. "But they believed, and I quote, 'that Jews have money,"' he said. "That's called anti-Semitism." He said the gang tried to kidnap six other people since December, four of them Jewish. The suspected gang leader, Youssef Fofana, a French citizen, was arrested Wednesday in Abidjan, Ivory Coast, and France is seeking his extradition. Fourteen people have been placed under investigation - a step short of being charged - in the case, and two more people were detained Friday for questioning.