PRISTINA, Kosovo (AP) — Kosovo police say an opposition party member in detention has died under still unclear circumstances.

A police statement Sunday said an autopsy would be conducted to clarify what killed opposition Self-Determination Movement activist Astrit Dehari.

The movement is blaming the government for Dehari's death and expressing doubts about media reports suggesting he arrived dead at a hospital after allegedly swallowing a fatal dose of prescription medicine.

Dehari and five other party supporters were arrested in late August for their alleged involvement in a rocket-propelled grenade attack on Parliament that damaged the building's exterior but caused no casualties.

The Aug. 4 attack occurred amid political tensions over the government's August 2015 agreement with neighboring Montenegro determining their common border.

Opposition parties vehemently oppose the deal, arguing it cedes territory to Montenegro.