That depends on which version of Lightroom you are referring to. If Lightroom Classic then the images that are deleted go to the recycle bin or the trash. In that case they are still on the hard drive until you empty that receptacle. In Lightroom Classic images are not "in" Lightroom, they are in folders on your hard drive. If you chose to store copies then those copies are in folders wherever you chose to have them stored.
If you are referring to Lightroom (for the cloud) then the master images are stored in the cloud and if you have chosen the option to store copies locally then they are stored wherever you have designated them to be stored in the Lightroom preferences.