Between 1836 and 1840, relations between Smaïl-aga and the Christian inhabitants of his land had greatly deteriorated. Smaïl-aga's son, Rustem-beg, drank heavily and often raped women from the Drobnjaci and Pivljani tribes while stopping by their villages to collect tribute. Furious, the Drobnjaci approached Njegoš and asked him for help killing Rustem-beg. Njegoš reasoned that by killing Rustem-beg he would risk infuriating Smaïl-aga, prompting him to seek vengeance against Njegoš, as well as the Drobnjaci and Pivljani. Instead, he persuaded the tribes to assassinate Smaïl-aga himself, as well as his closest associates, leaving Rustem-beg unprotected and powerless to avenge his father's death. The Drobnjaci heeded Njegoš's advice and organized a plot to have Smaïl-aga killed. In early September 1840, some of the Drobnjaci rebelled and refused to pay tribute to Smaïl-aga's son, instead daring Smaïl-aga to come to their villages and collect it himself. Smaïl-aga arranged for a carriage procession to Drobnjaci and set up camp in Mljetičak, a hamlet overlooking the town of Nikšić. On 23 September, he and his delegation were ambushed by a band of 300–400 Drobnjaci warriors led by Novica Cerović, Đoko Malović and Šujo Karadžić. Smaïl-aga attempted to flee but discovered that a spy had hobbled all the horses. He was surrounded in his tent and shot by one of the Drobnjaci warriors; forty other Turks were killed in the ambush. Once Smaïl-aga was dead, the warrior Mirko Aleksić severed his head with an axe. Cerović then took the head to Cetinje and presented it to Njegoš. Satisfied with the outcome of the plot, Njegoš rewarded Cerović by making him a senator.