Israeli police said Thursday they arrested three more suspects in attacks by members of the Druze minority on military ambulances transporting wounded Syrians to hospital.
In one of two incidents Monday, one Syrian was beaten to death and a second hurt, in an unprecedented outbreak of violence by Druze on the Israeli-occupied Golan Heights that Prime Minister Benjamin Netanyahu called a "lynching."
Syria's Druze are traditional allies of President Bashar al-Assad, and have become caught up in the fighting.
"During the night, police and border guards in the north arrested three more suspects from the Druze community suspected of involvement in the events," police spokeswoman Luba Samri said in a statement.
She said a gag order had been imposed on all other details of the investigation.
Police said they carried out a "wave of arrests" Wednesday, with media saying nine people had been detained.
Monday's deadly incident took place hours after Druze in the neighbouring Galilee region of Israel blocked and stoned a military ambulance they suspected was taking Syrian rebels to hospital.
Both incidents demonstrate the anger felt by Druze towards the rebels, and towards the Israelis, whom they suspect of providing medical help to the fighters.
Israel does not rule out the possibility that some of those given medical care are rebels.
Syria has said the two men in the ambulance were members of Al-Qaeda affiliate Al-Nusra Front. Israel says they were civilians.
The Druze are a secretive offshoot of Shiite Islam. Officials say there are 110,000 of them in northern Israel and another 20,000 in the Israeli-occupied Golan.
Israel seized 1,200 square kilometres (460 square miles) of the Golan Heights from neighbouring Syria in the 1967 Six Day War.