The people behind an alleged attempt to overthrow the government of Ethiopia's northern Amhara state wanted to kill more officials, a government commission has said.
Following Saturday's violence, five senior figures, including the head of the army Gen Seare Mekonnen, died as a result of what the government has called a coup attempt.
Three died in Amhara state and two were killed in the capital, Addis Ababa.
The Security and Justice Joint Task Force was formed to investigate what happened.
The task force says that 255 people have been arrested since Saturday, 212 in Amhara state and 43 in the capital.
On Thursday, an opposition party said more than 50 of its members had been detained.
The security forces have seized 27 AK 47 rilfes, two machine guns and an unspecified number of pistols.
The task force is looking into the possible link between the killings in Amhara and those in Addis Ababa. The government has said they were connected.