“Most of the ‘science’ of fire and explosive analysis has been conducted by insurance companies looking to find evidence of arson so they don't have to pay off their policies,”
https://www.scientificamerican.com/article/can-we-trust-crime-forensics/
Bloodstain-pattern analysis has been accepted as reliable evidence by appellate courts in one state after another with little or no examination of its scientific accuracy.
https://features.propublica.org/blood-spatter/blood-spatter-criminal-justice-courts-forensic-evidence/
The FBI faked an entire field of forensic science. (Microscopic hair analysis)
https://slate.com/news-and-politics/2015/04/fbis-flawed-forensics-expert-testimony-hair-analysis-bite-marks-fingerprints-arson.html