Q: His long can police stay outside your residential if you didn't answer or engage with them when they knocked on the door

A: The amount of time the police can remain outside your residence after attempting to make contact with you can vary depending on the specific circumstances and the laws of your jurisdiction. However, here are a few general points:

1. Reasonable time: Police officers are typically allowed to remain on your property for a reasonable amount of time to attempt to make contact with occupants or to conduct an investigation, even if you do not answer the door.

2. Probable cause: If the police have probable cause to believe that a crime has been committed or is in progress, they may be justified in remaining on the premises for a longer period or even entering the property.

3. Warrant: If the police have a valid search warrant or arrest warrant, they are allowed to enter your property to execute the warrant, even if you do not answer the door.

4. Exigent circumstances: In emergency situations, such as when the police believe someone is in imminent danger, they may enter your property without a warrant or permission.

Regarding the police attempting to open doors in your backyard, the legality of this action depends on the specific circumstances. If they had probable cause, a warrant, or believed there was an emergency situation, their actions might be justified. However, if they did not have a valid reason to be on your property or to attempt to gain entry, their actions could be considered an unlawful search.

If you believe that the police acted inappropriately or violated your rights, you should consider contacting a criminal defense attorney to discuss your situation and potential legal options.