If you have reason to know that police are looking for evidence in a case and you have it in your possession, you need to be very careful. It is a crime to dispose of evidence, and it is extremely unwise to try and turn it over to police on your own. It may also be a big mistake dropping it off at your lawyer's office. Most lawyers don't want to be put in that position, it could compromise the lawyer's ability to represent you. The first thing you should do when you learn that you have evidence in your possession is tell your lawyer about it confidentially. This scenario often arises after a search warrant has been executed by police who are looking for an object that you know they've missed. Don't give it to them, don't tell them, don't bring it to your lawyer's office. Tell your lawyer in confidence and let the lawyer decide how to deal with it.
For more information regarding your question, contact a criminal defense lawyer at Perez & Perez Law, PLLC.