Paul Pelosi managed to call law enforcement to the San Francisco home he shares with the House speaker during the attack in the early hours of Friday morning, by secretly dialling 911 from his cellphone and speaking in “code”, police said on Friday.
The 82-year-old left the line open as he spoke to Mr DePape, enabling the dispatcher to hear the interaction.
At one point, the operator reportedly heard Mr Pelosi asking: “What’s going on? Why are you here? What are you doing to me?”
In a police audio clip, from 2.28am local time, the dispatcher is heard telling another operator that the caller “stated that there is a male in his home and he is going to wait for his wife”.
The operator says that the caller – identified by the SF Chronicle as suspect David DePape – described himself as “a friend”.
He “stated that he does not know who the man is but said that his name is David and that he is a friend”.
San Francisco Police Chief William Scott praised the “intuition and quick-thinking” of the dispatcher who realised the call was suspicious and dispatched law enforcement to the property as an emergency.
The first police officers were on the scene within three minutes.
“She figured out there was something more to what she was being told, her actions resulted in a higher priority dispatch and a quicker police response. I think this was life-saving,” he said.
Police sources told CNN that Mr DePape was searching for Speaker Pelosi and entered the home shouting “Where is Nancy? Where is Nancy?”
The attacker then allegedly tried to tie Mr Pelosi up in the aim of waiting until his wife returned home.
The House speaker was in Washington DC at the time.
When officers arrived on the scene, the attacker allegedly said that they were “waiting for Nancy”.
Chief Scott said that “someone inside” the home opened the front door and the officers saw both Mr Pelosi and Mr DePape with their hands on one hammer.
At that moment, Mr DePape pulled the hammer away from Mr Pelosi and “violently assaulted” him with it, striking him at least once, the police chief said.
The officers tackled Mr DePape to the ground and administered medical aid to Mr Pelosi.
It is currently unclear if Mr DePape brought the hammer to the home or if it belonged to the Pelosis.
Mr Pelosi was taken to hospital where he underwent surgery for a skull fracture on Friday.
He also suffered “serious injuries” to his right arm and hands and is expected to make a full recovery.
The police chief condemned the attack describing it as “intentional” and “not a random act”.
“It’s wrong. Our elected officials are here to do the business of their cities, their counties, their states and this nation. Their families don’t sign up for this to be harmed and it is wrong,” he said.
Mr DePape, a 42-year-old resident of Berkeley, California, was arrested on charges of attempted homicide, assault with a deadly weapon, elder abuse, burglary and other felonies.
While the motive for the attack remains unclear, sources told KTVU that police found the assailant’s manifesto which detailed conspiracy theories and anti-government Covid-19 beliefs.
The manifesto also included a hit list of other lawmakers he planned to target, the sources said.
It is not clear whose names are on that list.
Mr DePape’s online history also reveals a deep-rooted obsession with extreme right-wing conspiracy theories.
In blog posts and social media pages, the 42-year-old spewed transphobic, antiSemitic and racist views, and pushed conspiracy theories about the Covid-19 vaccine, the Holocaust and QAnon.
He also revealed his support for Donald Trump to run in 2024 with Tulsi Gabbard as his running mate.
Speaker Pelosi has been the target of politically-motivated attacks and harassment in the past.
Friday’s encounter has chilling echoes of the January 6 riot when Donald Trump supporters – spurred by lies that the 2020 election was “stolen” – broke into the US Capitol and hunted for the House Speaker.
“Where’s Nancy?” the mob chanted as they ransacked her office, searching for her.
In one video posted online, a woman told the camera: “We were looking for Nancy to shoot her in the frickin’ brain. But we didn’t find her.”
Mr DePape, originally from British Columbia, is a hemp jewellery designer.
He is currently being held in San Francisco County Jail.
This article has been amended to clarify that it was David DePape – and not Paul Pelosi – who identified himself as “David” and said “a friend” in the dispatch call