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The police has always resulted to violence when a citizen refuse to give in to their usual harassment and when one resist arrest, he is being slam with charges for resisting arrest. In the U.S and the rest of the world. They are all the same, you get pull over and being issued a ticket for not using a seat and they claim is for your safety and when you refuse the ticket, one risk being arrested and end the police ends up using violence means to ensure the person accept to be taken in.
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In the U.S, many cases has been caught on tape about police brutality against the citizen. The same person who is suppose to protect you are same person using voilence to you. After such an incident, when one needed the police, can that same person trust the police to handle his/her justly. I will share a link to 
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In Africa, police brutality happens daily and even the judiciary is aware of this and nothing is done to curb this inhumane treatment melted on the citizen by the police. This has been ongoing for decades and no special attention is given to it.
The purpose of the creation of the police force has been defeated and hence see no reason for its existence
Does the police still protect life?
Will the police ever engage the real offenders and leave innocent citizens?
Can the police face the drug cartel and treat them this way?
What is the purpose of the police when they violate human rights?