With how common smartphones are these days, many people film encounters with police officers as evidence in case things go wrong. In stories that make the news, occasionally police dashcam videos show police officers erasing cellphone or dashcam videos captured by citizens, or in some cases destroying the devices themselves.
Is it illegal specifically for police officers to delete or destroy video evidence of their own encounters, captured by citizens?
Note: Because I'm sure this varies greatly from state to state, I'm asking in particular about New York and California, and the United States as a whole in case any federal law applies