I put something in the trash and cannot find it there now. I did not empty it

Items deleted from some sources may not be placed into the trash, but are deleted immediately. This may happen to files deleted from a remote server – another wi-fi connected Mac, for example.

Other times, if the file was deleted from an external drive, if the drive is disconnected the file will not be visible to you in the trash until the external drive is reconnected. Trash bins are local to the device (drive) the file was deleted from.