This is from Joe who commented to this blog:
Thousands of Colorado DUI convictions could be in doubt amid forgery allegations:
Colorado lawyers specializing in drunken-driving cases are questioning the validity of thousands of convictions after a technician who certified the state’s breath-test machines said his signature was forged on more than 100 records in 2013.
In addition, a former laboratory director’s signature is still being used on some certificates more than a year after she left the Colorado Department of Public Health and Environment in July 2015. Those certificates are being used in DUI trials to prove machines were recording accurate blood-alcohol content.
“This is the lab we’re asking to go into court and testify to the veracity of their machines,” said Darren Cantor, president of the Colorado Criminal Defense Bar. “It really makes me question whether the CDPHE is capable of doing that.”
http://www.denverpost.com/2017/03/14/colorado-dui-convictions-forgery-attorneys/
FORENSICS and LAW in FOCUS @ CSIDDS | News and Trends 
More evidence of police ‘oversight’ of forensics, regardless of certification by the commercial crime lab industry, is fraught with agenda conflicts and lack of fairness.