How can the CVR from a Cessna 560XL only contain old records and none from the fatal accident? Is it possible that the CVR from a Cessna 560XL is just showing old records and nothing from the fatal accident when the plane crashed?

I´m talking about the airplane crash in Brazil, where a election candidate was killed. The investigation team said that the data in the CVR contained only old data and they could not pinpoint from when those recordings were.
If the fuse was pulled between the previous flight and the crash then yes, the CVR can only record when it has power

Pulling the fuse or going behind the panel and cutting the wire will prevent it from recording.