[9][10][11] Months later, however, the Washington, D.C. medical examiner reported that Sicknick had died as a result of two strokes, classifying his death as due to natural causes,[a] but later commented that "all that transpired played a role in his condition".

[23]After struggling to find a job as a police officer, Sicknick joined the New Jersey Air National Guard in 1997 to strengthen his background for future applications.

[24] In 1998, he wrote a letter to Home News Tribune, his local newspaper, expressing his skepticism towards America's soft stance against Saddam Hussein.

[4] He was remembered by Caroline Behringer, a staffer for House Speaker Nancy Pelosi, for comforting her as she returned to work at the Capitol following Trump's 2016 victory.

Within five minutes of the pepper spray attack, rioters breached the police line and seized control of the west side of the building.

[30][35] The chief medical examiner, Dr. Francisco J. Diaz, told The Washington Post that there was no evidence that Sicknick was injured or had an allergic reaction to chemical irritants.

[6] On January 8, the United States Department of Justice published a statement by Acting Attorney General Jeffrey A. Rosen, which attributed Sicknick's death "to injuries he suffered defending the U.S. Capitol, against the violent mob who stormed it".

[9][38][10] On January 8, the Associated Press,[25] The Wall Street Journal,[40] and separate stories in The New York Times cited two anonymous law enforcement officials as saying that Sicknick was struck in the head by a fire extinguisher.

A memorandum for the second impeachment trial of Donald Trump stated "The insurrectionists killed a Capitol Police officer by striking him in the head with a fire extinguisher".

[46] On the same day, CNN reported that according to a law enforcement official, medical examiners had not found evidence of blunt force trauma on Sicknick's body.

[48][10] On February 12, the Times hedged its initial reporting with an update posted to the story[49] and Sicknick's autopsy found no evidence of blunt force trauma or either internal or external injuries.

[31] In April and May 2021, Senator Ron Johnson (R-WI) sent letters to the acting U.S. Capitol Police chief requesting information on the handling of Sicknick's death.

[7] The next day, the USCP opened a homicide investigation into Sicknick's death,[51] joined by the D.C. Metropolitan Police Department and other federal agencies.

[47] On March 14, Julian Khater and George Tanios were arrested by federal authorities and charged with crimes that included assault of Officer Sicknick with a chemical spray.

[3] On January 27, 2023, Khater was sentenced to 6 years and 8 months in prison after pleading guilty to assaulting Capitol Police officers, including Sicknick, with a keychain pepper spray.

[53] In January 2023, Sicknick's partner, Sandra Garza, filed a civil case for wrongful death and conspiracy (among other claims) against Trump, Khater and Tanios, $10 million from each defendant.

[57] Outgoing Vice President Mike Pence called Sicknick's family to offer his condolences, and a deputy press secretary for the Trump administration issued a written statement.

[63] On January 29, Pelosi and Senate Majority Leader Chuck Schumer announced that Sicknick would lie in honor at the Capitol rotunda.

[65] Vice President Kamala Harris and Second Gentleman Doug Emhoff paid their respects on February 3, along with several legislators and police officers.

[66] Later that day, Sicknick's cremated remains, accompanied by a procession, departed the Capitol for Arlington National Cemetery, where burial took place.

[21] Members of Sicknick's family attended Super Bowl LV in February 2021 as honored guests of the National Football League, along with three officers of the Metropolitan Police Department.

[70][71] At the December 2022 Congressional Gold Medal ceremony, Sicknick's family members refused to shake the hands of Republican leaders Mitch McConnell and Kevin McCarthy.

[72] On January 6, 2023, for his role in defending the U.S. Capitol, Sicknick was posthumously awarded the Presidential Citizens Medal by President Joe Biden.