Private security footage is nothing new to criminal investigations, but two factors are rapidly changing the landscape: huge growth in the number of devices with cameras, and the fact that footage usually lands in a cloud server, rather than on a tape.
When a third party maintains the footage on the cloud, it gives police the ability to seek the images directly from the storage company, rather than from the resident or business owner who controls the recording device. In 2022, the Ring security company, owned by Amazon, admitted that it had provided audio and video from customer doorbells to police without user consent at least 11 times. The company cited “exigent circumstances.”
Sadly the average person buying such proprietary cameras does not possess the technical know how for that. Also the average person buying those ultimately also does not care about privacy, unfortunately. They definitely should, but they usually don’t.