Video Footage of Attack on Paul Pelosi Shown at San Francisco Hearing

Among the evidence was body-camera footage of the attack, showing that when the police arrived, Mr. Pelosi and Mr. DePape were standing, each with a hand on a hammer. They appeared calm, until an officer told them to drop the tool. That is when Mr. DePape took control of the hammer and lunged at Mr. Pelosi, striking him once, according to the video.

“Really hard,” Mr. Cagney said when asked by a prosecutor to describe the force of the hammer attack. During his testimony, Mr. Cagney showed the court the hammer, measuring more than a foot long, that he said was used to bludgeon Mr. Pelosi.

The hearing began with prosecutors playing a recording of a call that Mr. Pelosi made to 911 shortly after the intruder woke him up. During the call, Mr. Pelosi speaks calmly but emphatically, seemingly trying to convey to the operator that he is in danger but without alarming the intruder threatening his life.

Mr. Pelosi said on the call that there was “a gentleman here waiting for my wife to come back.” He told the operator who his wife was, and at one point the intruder in the background could be heard saying, “The name is David.”

Mr. DePape faces multiple felony charges in state court, including attempted murder and assault with a deadly weapon. The Justice Department has also accused him of the federal crimes of attempted kidnapping of a federal officer and assault on a family member of a federal official. If convicted, Mr. DePape could spend the rest of his life in prison.

Ms. Pelosi will no longer be speaker next month since Democrats lost control of the House during the midterm elections, albeit by a slimmer margin than had been expected. She also will step down as the leader of House Democrats, giving way to Representative Hakeem Jefferies of New York, who will take her place.

Mr. Pelosi spent six days in a San Francisco hospital, where he underwent surgery for a skull fracture and treatment for injuries to his hands and right arm. Ms. Pelosi said after the attack that he was facing “a long recovery process.” Earlier this month, Mr. Pelosi made his first appearance in public since the incident by attending the Kennedy Center Honors with his wife in Washington.