MINNEAPOLIS -- The state of Minnesota is suing the maker of an instrument used to test drunken-driving suspects, saying it needs to see the software that runs the machine.

It's the instrument that for years, has been tried, tested and trusted by police departments across Minnesota to measure just how drunk a suspected drunk driver really is.

"This is the Intoxilyzer 5000 MN model," Sgt. Bill Palmer shows us the breath test used by the Minneapolis Police Department.

But now, the trusted Intoxilyzer is being questioned by defense attorneys like Marsh Halberg.

"We handle hundreds of DWI cases a year," says Halberg of his Twin Cities law firm.

Over the last year, Halberg and other Minnesota attorneys defending clients charged with being over the legal driving limit of .08 have asked the state to give them what's known as a source code, which is essentially the computer code that makes the Intoxilyzer work.

"We want to have the ability scientifically, to analyze the source code and the way this computer runs," says Halberg. "We say we want to get inside there to figure out why if you blow at one end, the number comes out at the other end that says you've had too much to drink."

The problem is, whenever the state - even with a court order - asks the company that makes the Intoxilyzer for that code, the company refuses. Kentucky-based CMI produces the Intoxilyzer.

The state is now suing CMI in federal court. According to the lawsuit, the company argues the code is a trade secret.

And while the state itself doesn't question the accuracy of the Intoxilyzer, the source code issue has become a problem. Many judges are now throwing out drunken driving cases because the state can't produce the code.

"This is without exaggerating a life and death issue. If you had a relative or a friend or a neighbor that got killed by a drunken driver, you'd take this very seriously," says Minnesota Commissioner of Public Safety Michael Campion. "The fact that cases might be potentially dismissed, that justice will not go forward, is justice delayed and we felt very strongly that we needed to get this issue resolved and to move forward on it."

The state has also had to reinstate many revoked drivers licenses because of this.

And as a result, some law enforcement agencies have stopped using the Intoxilyzer altogether and are now relying only on blood and urine tests to measure blood alcohol level. But the state says that is straining state laboratories.

KARE 11 did try to contact CMI, but were unable to reach company officials. There are 260 Intoxilyzers in Minnesota. 35,000 breath tests were done last year.

(Copyright 2008 by KARE. All Rights Reserved.)