You value your privacy, so you have your cellphone locked. No one can use it without typing in a passcode or using biometric data. For instance, maybe you have a fingerprint scanner on the phone, which prevents unauthorized entry unless you give someone else a code.
However, say that the police want to look at your phone for some reason, such as if you have been accused of internet crimes and they want to search for evidence on your device. You tell them that you do not want to unlock your phone for anyone, so you refuse to do it. In response, the officer physically takes your hand and forces you to touch the fingerprint scanner, unlocking the device without your consent. Is this legal?
This is a violation of your rights
This is not legal, and it is a violation of your rights under the Fourth Amendment. Just as the police cannot illegally search your car or your home, they cannot search your phone. They need to have your consent or a search warrant to do so.
In fact, it does not even matter if the police were correct that there was evidence on your phone. Say that they find text messages admitting to a conspiracy to commit financial crimes. They may think that this justifies the search, but it does not. Whether there is evidence on the device or not, it is still a violation of your rights for them to force you to unlock that device without getting your consent or first obtaining a court-issued search warrant.
If you are facing these types of civil rights violations, it is crucial that you understand all of the legal options at your disposal.