Amir Locke's family and attorneys pleaded Wednesday for federal authorities to investigate his death and pass a national ban on no-knock warrants after Minnesota prosecutors announced they would not charge the officer who killed him.

"This is an example of why we cannot stop fighting for federal law, because this is a slap in the face, to not only his mother and family, but to all of us," the Rev. Al Sharpton said at a New York news conference. "There cannot be an allowance of no-knock laws, nowhere in this country."

Karen Wells, Locke's mother, echoed his remarks, saying her son, who was Black, made efforts to ensure he was legally carrying the gun he used for protection while working in food delivery. He appeared to have been denied the same rights given to other gun owners, she said, because "he has too much melanin."

"So get ready," Wells said. "... We're coming full force. I'm not gonna stop racing this race."

The family's news conference came hours after Minnesota Attorney General Keith Ellison and Hennepin County Attorney Mike Freeman announced they would not charge officer Mark Hanneman, who fired the shots that killed Locke. It came less than a day after Minneapolis Mayor Jacob Frey announced a ban on no-knock warrants — though critics say it has loopholes .

Later Wednesday evening, a few dozen people stood in the rain outside the Hennepin County Government Center, condemning the no-charge decision and calling for state and federal bans on no-knock warrants.

Policy gains attention

The death of Locke, 22, in February reignited a national debate about no-knock warrants, which don't require officers to announce their presence before entering a residence. Minneapolis police were searching a downtown apartment on Feb. 2 when, seconds after entering, Locke, who appeared to have been sleeping on a couch, stirred under a blanket while holding a gun. Hanneman shot Locke, who died the same day.

Local and national groups called on Frey to ban no-knock warrants, something his campaign had falsely claimed he had already done. On Tuesday, Frey unveiled a new policy

that prohibits officers from obtaining or executing no-knock warrants, but it still allows them to obtain other types of warrants and enter without announcing their presence in "exigent circumstances." The policy defines "exigent circumstances" as when in hot pursuit, to prevent imminent harm or provide emergency aid, to prevent imminent destruction or removal of evidence and to prevent the imminent escape of a suspect.

Katie Lauer, a spokesperson for Frey said: "The mayor wanted to make sure that exigent circumstances were the only reason that immediate entry would happen. These are provided for in state law and we have further restricted what constitutes an exigent circumstance in our policy."

Some activists are leery of the exception for exigent circumstances, saying the city has promised to restrict no-knock warrants before and didn't deliver .

"I would imagine that MPD could use that as a justification to continue not waiting to enter," said Pete Gamades, a member of the Racial Justice Network.

Officers were using a no-knock search warrant when they entered the apartment where Locke was killed. According to a report prepared by a police practices expert for prosecutors, the application said police believed they needed one "both for safety reasons and to prevent the destruction of evidence." Among other things, it noted that a person — whose name is redacted — had fled from the homicide scene to the apartment building where the search occurred and that surveillance video showed someone "seemingly hiding the murder weapon under his clothing."

It wasn't immediately clear whether that would have allowed them to enter without announcing under the new policy.

Attention turns to Capitol

Some activists and elected officials are turning to the state and federal governments as they seek greater restrictions or bans on no-knock warrants.

Ellison called on officials to "interrogate whether no-knock warrants are ever really needed." Freeman's office added: "The fact that it is standard practice for paramedics to stand by at the scene when no-knock warrants are executed speaks to the foreseeably violent nature of this law enforcement tool."

DFL lawmakers in the Minnesota House are trying to move legislation that would ban no-knock warrants. Gov. Tim Walz has said he would sign a bill banning the practice.

The new bill defines no-knock search warrants as any warrant authorizing an officer to enter a property without first "loudly knocking and loudly and understandably announcing the officer's presence or purpose and waiting no less than 30 seconds thereafter prior to entering the premises to allow compliance by the subject."

The proposal, introduced by Rep. Athena Hollins, DFL-St. Paul, was put forward after Locke's death earlier this year.

There is no companion bill in the Republican-controlled Minnesota Senate. State Sen. Warren Limmer, the Maple Grove Republican who chairs the Senate's judiciary and public safety committee, has said that he was inclined not to support the proposed ban, noting previously that "there are times when you have to use extreme measures" to arrest dangerous criminals. He has instead opted to focus on increasing penalties for certain crimes and changes to the Minnesota Sentencing Guidelines Commission.

The Locke family's team is now focusing on the federal government. Part of the problem, Sharpton said, is "we're dealing with states' rights legislation around no-knock laws. ... So it must be federal law."

Staff writers Andy Mannix, Katie Gallioto, Faiza Mahamud and Abby Simons contributed to this report.