In one of several events across New York City honoring George Floyd Tuesday, Mayor Bill de Blasio and Rev. Al Sharpton knelt for nine minutes and 29 seconds at the National Action Network in Harlem.

Floyd was killed one year ago when former Minneapolis police officer Derek Chauvin knelt on the back of his neck for the same amount of time during a controversial arrest, adding fuel to the Black Lives Matter movement.

“We saw a murder before our eyes committed by someone who was supposed to exemplify law, who was supposed to protect,” de Blasio said.

Chauvin was convicted of Floyd's murder in April.

Activists say more needs to be done and are calling on Congress to pass the George Floyd Justice in Policing Act. Among other things, the law would require that officers only use deadly force as a last resort as well as make it easier to track and discipline officers who are accused of misconduct.

The bill passed in the U.S. House of Representatives in March, but still needs to pass in the Senate before President Joe Biden could sign it into law.