If you arrest the wrong person, then the real criminal gets away. So your question's moot as either way the criminal gets away.
Usually, it means you helped someone commit a crime.
That would depend upon what crime you commit, the severity of the crime and your criminal record.
Just commit a crime and you will be considered a criminal.
When they commit an arrestable crime and are caught.
There is no such thing. Even if the crime was unsuccessful in being carried out, the attempt to commit it satisfies the legal requirement of a criminal act accompanied by a criminal intent.
A person who commits a crime is known as a criminal.
the motive
The General principle says that in every crime there are four successive stages in its commisiion,viz., 1)Intention to commit a crime; 2)Preparation to commit a crime; 3)Attempt to commit a crime; and 4)The actual commisssion of the offence.
If you commit a crime in Mexico, you may face legal consequences such as arrest, prosecution, and potential imprisonment. The severity of the punishment will depend on the nature of the crime committed.
Crime Control
A person is "under arrest" when a police officer charges them with a crime and chooses to take them to the police station to be processed for it. For example, if someone commits a crime, they are technically under arrest when a police officer witnesses the crime or has a warrant for the arrest and tells the criminal "You are under arrest." Typical procedure after this is to put handcuffs on the criminal and read them their Miranda rights (you have the right to remain silent etc). Handcuffs alone do not mean arrest, but i'm pretty sure its illegal for a police officer to handcuff someone without grounds to arrest them. As a side note, the person doing the arrest does not have to be a sworn in police officer. In Citizen's arrest cases, anyone with arresting powers like a bounty hunter can also place someone under arrest.
An accomplice is a person who helps someone else commit a crime. Their involvement can impact criminal activities by aiding in the planning, execution, or cover-up of the crime, making it more likely for the crime to be successful and harder for law enforcement to solve. Accomplices can also be held legally responsible for the crimes they help commit.