WASHINGTON — A federal judge sentenced a California man who launched one of the most vicious, prolonged assaults on police on Jan. 6 to 20 years in prison Friday — handing down the second-longest Capitol riot sentence to date.
In a sentencing memo filed last week, prosecutors said David Nicholas Dempsey, a former construction worker from Van Nuys, assaulted police for more than an hour as they were attempting to prevent a violent mob from entering the U.S. Capitol through the Lower West Terrace Tunnel. The tunnel was the site of some of the most intense fighting between police and rioters that day, and prosecutors described Dempsey as one of the primary components of that fighting.
“Dempsey was one of the most violent rioters, during one of the most violent stretches of time, at the scene of the most violent confrontations at the Capitol on January 6, 2021,” prosecutors wrote. “Unlike other rioters who slowly pushed their way through the crowd towards the Capitol, Dempsey climbed atop his fellow rioters, using them like human scaffolding, thrusting himself to the front. Once he reached the mouth of the tunnel, Dempsey began a prolonged attack, fighting with his hands, feet, flag poles, crutches, pepper spray, broken pieces of furniture, and anything else he could get his hands on, as weapons against the police. Dempsey’s violence reached such extremes that, at one point, he attacked a fellow rioter who was trying to disarm him.”
Dempsey pleaded guilty in January to two felony counts of assaulting police with a dangerous or deadly weapon for assaults on two DC Police officers – Det. Phuson Nguyen and Sergeant Jason Mastony – but prosecutors said those were only a small portion of the assaults he committed that day.
In their memo, prosecutors described how Dempsey emptied a can of pepper spray against Nguyen before throwing it at other officers in the tunnel. A minute later, he swung a metal crutch at the line of officers at least nine times. One of those swings hit Mastony in the head – slicing it open and causing him to collapse to the ground, believing he’d suffered a concussion. A second swing hit Mastony in the arm. Prosecutors said Dempsey also:
- Swung a collapsible metal pole seven times at police, striking officers’ hands, arms and helmets;
- Swung a long wooden pole at police, hitting one in the head, before throwing it at officers;
- Threw multiple objects at officers, including a flagpole, broken pieces of wooden furniture and a bottle of an unknown white substance;
- Climbed up on top of other members of the mob and stomped on officers from above, as well as another rioter who attempted to pull a pole away from him.
In addition to his assaults on police on Jan. 6, prosecutors said Dempsey has a “very significant history of arrests.” They include a 2021 assault with a caustic chemical conviction in Los Angeles, a conviction in 2017 for fleeing officers after breaking into a cellphone store for which he received five years in prison, and multiple other burglary and assault cases.
Prosecutors said the assault with a caustic chemical case foreshadowed his assaults on police on Jan. 6. In that case, a peaceful demonstration against then-President Donald Trump near the Santa Monica Pier turned violent after Dempsey dispersed a canister of bear spray against several protesters at close range.
Dempsey, prosecutors said, also committed at least three other “documented instances of vicious political violence” for which he was never charged. They include, prosecutors said, a June 2019 assault in L.A. during a political rally in which he hit a counter-protester over the head with a skateboard and an August 2020 assault in Beverly Hills in which he wrestled a protester to the ground, pepper sprayed him at close range and then repeatedly hit him in the head with a metal bat.
On Friday, Assistant U.S. Attorney Douglas Brashers described Dempsey as "political violence personified and asked U.S. District Judge Royce C. Lamberth to sentence him to 262 months, or more than 21 years, in prison.
Dempsey's attorney, Amy Collins, argued her client shouldn't be treated as a domestic extremist like other Jan. 6 defendants who came as part of organized groups. She sought a much lower sentence of 78 months, or 6.5 years, in prison.
Dempsey himself read a letter he'd written on Friday, telling Lamberth he'd come before him with a "profound sense of regret" about what he'd done on Jan. 6.
"My grandpa taught me never to hit a man when he was down or had given up," Dempsey said. "Unfortunately I made that choice several times that day."
But Dempsey also seemed to continue to blame police for much of the violence on Jan. 6 as he described seeing rioters being "pummeled by fully armored men" who he considered "bullies."
Lamberth, who has sentenced dozens of Jan. 6 defendants, told Dempsey his conduct during the riot was "exceptionally egregious" and declined to grant a downward variance, citing in part Dempsey's "long and well-documented history of inflicting violence on political opponents."
Lamberth sentenced him to 240 months, or 20 years in prison, to be followed by three years of supervised release. Dempsey will also have to pay $2,000 in restitution to the Architect of the Capitol and may be ordered to pay additional restitution to the officers he assaulted at a later hearing.
Dempsey's sentence is the longest handed down to date for any Capitol rioter not convicted of seditious conspiracy, and the second-longest overall behind former Proud Boys national chairman Enrique Tarrio, who received 22 years behind bars. Prior to Friday, the longest non-conspiracy sentence was held by Peter Schwartz, a Pennsylvania man with 38 prior convictions prior to Jan. 6 who was sentenced in May 2023 to 14 years in prison after being convicted by a jury on 13 counts, including four separate counts of assaulting police with dangerous weapons and three other weapon-related felonies.
Dempsey's attorney asked for a recommendation he be placed at FCI Danbury, a low-security facility in Connecticut or one of several facilities in Oregon.
As he was being escorted out of the courtroom by U.S. Marshals on Friday, Dempsey held up the "OK" symbol above his head. The symbol's use as a political signifier was adopted on the right during former President Donald Trump's term in office and can be seen being flashed by participants in numerous photos during the Capitol riot.