The Fourth Amendment of the US Constitution guarantees its citizens protection against "unreasonable searches and seizures".
Holder said that DOJ found "systemic deficiencies" in Cleveland police practices that include "insufficient accountability", "ineffective policies" and "inadequate engagement with the community".
Holder is currently holding roundtable meetings on community trust across the United States as part of a US government response to the protests against US police officers abusing power.
The protests were sparked by Wednesday's grand jury decision not to press charges against police officer Daniel Pantaleo who chocked African-American Eric Garner to death in July and last week's grand jury ruling not to indict white police officer Darren Wilson for the deadly shooting of African-American teenager Michael Brown in August.
On Thursday, Holder said DOJ was going to launch a civil rights investigation into Garner's death.