The hearing of former Interior Minister Habib el-Adly and six top police officials was broadcast live on Egyptian state television.
The seven first appeared in court on Wednesday in the same defendants' cage with Mubarak and his two sons - one-time heir apparent Gamal and businessman Alaa - in a related case that is tried by the same judge. The Mubaraks' trial resumes Aug. 15.
Mubarak, el-Adly and the six police officials face the death penalty if convicted over the protesters' deaths.
The three Mubaraks separately face corruption charges.
El-Adly was Mubarak's interior minister for more than a decade, in charge of the country's 500,000-strong security forces. Some of the worst human rights abuses during Mubarak's 29 years in office are blamed on el-Adly and his police force.
Thursday's hearing was entirely taken up by procedural matters, with Judge Ahmed Rifaat opening boxes of evidence with defense lawyers looking on. The evidence included operational police logs covering the time of the uprising - Jan. 25 to Feb. 11 - with details about the movement of forces, issuing firearms and ammunition.
They also included several weapons and ammunition rounds. One piece of evidence was the blood-soaked jacket of one of the 850 protesters killed during the 18-day uprising.
The judge gave the lawyers a week to examine the evidence before hearings resume on Aug. 14.