PARIS — The last Serbian fugitive wanted by a United Nations war crimes tribunal was arrested in a Serbian forest early Wednesday, a quiet event that appeared to remove the final major obstacle blocking the nation’s access to Western money and European Union membership.

The suspect, Goran Hadzic, 52, is a former Serbian rebel leader who is accused of committing war crimes and crimes against humanity. He was arrested near the village of Krusedol in northern Serbia as he was about to meet “with a helper, who was supposedly bringing him some money,” said Vladimir Vukcevic, the war crimes prosecutor in Belgrade, Serbia’s capital.

Mr. Vukcevic said investigators had caught up with Mr. Hadzic recently because he had apparently run out of money after seven years on the run and was trying to sell a painting by Modigliani. “He was penniless,” Mr. Vukcevic said.

Investigators in Belgrade said the painting was believed to be “Portrait of a Man,” one of several Modigliani works listed as stolen. But it was not clear if the painting was authentic or a fake.