Only if the defendant doesn't challenge the evidence. If I'm the defendant and I know I sent those emails, I'm not going to challenge the screenshot. If I know

Only if the defendant doesn't challenge the evidence. If I'm the defendant and I know I sent those emails, I'm not going to challenge the screenshot. If I know I did not send those emails, then I'll do my best to pay for forensic analysts to generate evidence to exonerate me.