Your constitutional rights protect you from being arrested unless certain conditions are met. These conditions are referred to as "probable cause." If you are detained without probable cause, you may use this as a reason to sue the police department.
How The Officer Can Prove Probable Cause
The officer can use any of his or her senses to detect the commission of a crime. This is important because an officer can even arrest someone if he or she smells an illegal substance on you. The officer can also use scientific instruments, such as a breathalyzer, to obtain the probable cause necessary to arrest you.
A common situation in which probable cause is used is when a motorist is driving while intoxicated. The act of swerving can serve as evidence that the individual is under the influence. Then, asking the motorist to walk in a straight line can further give the officer probable cause to detain the motorist.
A police officer does not have the right to detain you unless he or she has probable cause. This is when the officer has reason to believe you have committed a crime or have violated a traffic law. Probable cause requires the officer prove it is more likely than not that you would have committed a crime. This can come from an object that you are in possession of, a statement that you have uttered, an action the officer witnessed or even information from an informant. If the officer relies on an informant, he or she must prove that the informant is reliable. Also, if there is a witness that informs the officer that you committed the crime, this can also be used as an excuse for probable cause.
Your Conversation With the Officer
Even though the officer is not allowed to search you without probable cause, he or she does have the right to talk to you. Also, you have the right to remain silent. The officer may try to have a conversation to encourage you to make a statement that could be misconstrued to provide the officer with probable cause.
You will need to find out exactly what justification the officer used to arrest you if you would like to begin poking holes in his or her justification. A criminal defense attorney will gather the facts of the case and will use them to determine whether the officer was justified in arresting you.