A woman reacts as she lays flowers outside the Perm State University following a campus shooting in Perm, about 1,100 kilometers (700 miles) east of Moscow, Russia, Tuesday, September 21, 2021. A student opened fire at the university, leaving a number of people dead and injured, before being shot in a crossfire with police and detained. Beyond saying that he was a student, authorities offered no further information on his identity or a possible motive. (Photo by Dmitri Lovetsky/AP Photo)

Gunfire was brought to the steps of President Truman's Washington home, Blair House, as two assassins tried to kill the chief executive, November 1, 1950. One of the gunmen, Oscar Collazzo of New York, lay wounded at the bottom of Blair House's front steps after the president's police guard had finished their work, at the cost of one guards' life, Dec. 9, 1950. The second gunman was killed. (Photo by Harvey Georges/AP Photo)

A Russian police officer detains a teenager during rally protesting retirement age hikes in St. Petersburg, Russia, Sunday, September 9, 2018. A government plan to increase the age for collecting state pensions brought protests across Russia's 11 time zones on Sunday even though the opposition leader who called them was in jail. Nearly 300 people were reported arrested. (Photo by Roman Pimenov/Interpress photo via AP Photo)

In this September 27, 2017 file photo, girls walk past a wall riddled with bullet holes from shootings between rival drug traffickers, at the Rocinha slum, in Rio de Janeiro, Brazil. Violence is on the rise in Rio's slums after several years of decline, and the killings of kids have shocked even residents long inured to deaths from gangs and police. (Photo by Silvia Izquierdo/AP Photo)

Demonstrators march in Port-au-Prince on February 14, 2021, to protest against the government of President Jovenel Moise. Several thousand people demonstrated Sunday in the Haitian capital Port-au-Prince, saying the government was trying to establish a new dictatorship and denouncing international support for President Jovenel Moise. The protests were mostly peaceful, although a few clashes broke out between some demonstrators and police, who fired tear gas and rubber bullets. (Photo by Valerie Baeriswyl/AFP Photo)

A young female demonstrator is arrested by police during clashes in the Causeway Bay area of Hong Kong, China on October 6, 2019. Hundreds of thousands of protesters marched through the city's streets in defiance of the new “no-mask” law, which was introduced two days ago as demonstrations roll into a 14th week. (Photo by Rick Findler/EPA/EFE/Rex Features/Shutterstock)

A demonstrator is detained by riot police during a protest, in La Paz, Bolivia on November 21, 2019. Bolivia's interim President Jeanine Anez asked Congress Wednesday to approve a law that would allow for new elections, after deadly unrest following the resignation of Evo Morales and the disputed October 20 ballot. (Photo by Marco Bello/Reuters)

In this January 23, 2021, file photo, a police officer detains a young woman during a protest against the jailing of opposition leader Alexei Navalny in Pushkin square in Moscow, Russia. Allies of Navalny are calling for new protests next weekend to demand his release, following a wave of demonstrations across the country that brought out tens of thousands in a defiant challenge to President Vladimir Putin. (Photo by Alexander Zemlianichenko/AP Photo/File)