A record number of convicts were exonerated last year, fueled by a backlog of lab tests that cleared drug suspects in Houston and a string of murder cases linked to a single New York City detective.

The National Registry of Exonerations recorded 125 in 2014 — up from 91 in each of the previous two years. The exonerees range from murder suspects convicted with tainted evidence to drug users who had their records wiped clean on a technicality.

The stage is set for an even higher number of exonerations next year because Harris County, Texas, is still working through a mountain of drug test results that could invalidate convictions.

“I’ve got about 400 reports,” said Nicolas Hughes of the Harris County Public Defender’s Office, who is handling the cases on behalf of the defendants. “My goal is to get them all done within this year.”