In video images, a group of riot police officers are heard cursing at Mr. Saber on Friday night as they beat him on the ground and drag him across a street to an armored vehicle. A witness, Mai Sirry, said that when she saw Mr. Saber, his pants were around his knees. In its initial statement, the Interior Ministry said it regretted the beating and called it an “individual attack” that did not reflect police doctrine.

Later, though, in a television interview, Mr. Saber gave an account of the beating from his hospital bed in which he said the officers had come to help as he was running from a group of protesters who had stripped and robbed him. They had apparently thought he was an officer, he said, and left him alone after deciding he was “just an old man.”

“I was afraid,” he said, adding that as he ran away from the protesters, officers came to help. He ran from them too, but they pulled him back, he said, telling him he would die if he did not let them help him.

A woman who identified herself as Mr. Saber’s daughter Randa, speaking Saturday on another Egyptian channel, said her father was being prompted to lie during the interview and was “afraid to talk.”