Lengthy crime lab delays have forced at least 21 people across Texas to serve time in prison or jail on drug possession charges when the substance they had wasn't actually illegal.
The Austin American-Statesman reports that all pleaded guilty and began serving time before confiscated samples came back from public labs for conclusive identification.
Because of lab backups or delays, the test results declaring 14 men and seven women innocent didn't arrive until months or, sometimes even years, later.
And prosecutors say there are almost certainly more such cases -- but no one is keeping close count.
The false-positive drug tests date to 2005, but they have become more common lately. In just the last two years, 14 people wrongly convicted have earned belated exonerations.