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Minnesota Bureau of Criminal Apprehension Superintendent Drew Evans said Friday that agency scientists are prepared to testify to the accuracy of questionable breathalyzer tests after a ‘mathematical recalculation’ of each test to correct for data entry errors. 

 to temporarily stop using the state’s fleet of DataMaster alcohol breath-testing machines after calibration errors rendered hundreds of DWI tests in multiple counties legally inadmissible. 

The following week, Evans said that the problem was not with the machines, but that some local law enforcement officers had 

 alcohol concentration values printed on gas cylinders that are used to provide control samples.

At a news conference, Evans said that BCA laboratory scientists recalculated each of the tests using the correct cylinder values.

“These recalculations have confirmed that the control tests remained within acceptable margins despite the data entry errors, meaning that the tests are reliable and accurate,” Evans said.

Attorney Dan Koewler, who along with his law partner Chuck Ramsay discovered the problem, which led to the initial invalidation of 73 breath tests in Aitkin County, said in a phone interview with MPR News on Friday that he will continue to challenge any criminal charges based on the faulty tests.

“The point of forensic science is to have that confidence in that final result because everything leading up to it was accurate, valid, and reliable,” Koewler said. “And now we’ve got this new unheard-of procedure where they’re trying to put a band-aid on something that never should have required a band-aid in the first place.”

Besides Aitkin County, the BCA said previously that there were problems with tests in Winona, Chippewa, Hennepin and Olmsted counties. 

After the problems arose, the BCA revamped procedures for calibrating the machines and said that only BCA staff, and not local law enforcement personnel, will change the control cylinders and enter the alcohol concentration data. 

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The Minnesota Bureau of Criminal Apprehension said that agency scientists are prepared to testify to the accuracy of questionable breathalyzer tests after a ‘mathematical recalculation’ of each test to correct for data entry errors. 

BCA stands by breathalyzer data after 'recalculation' of faulty tests

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