INDIANAPOLIS -- Accusations that an Indianapolis police officer was drunk when he caused a fatal crash have raised questions about how he was able to drink on the job and why his co-workers didn't notice.

Officer David Bisard, who was on duty when he plowed into a group of motorcyclists stopped at a red light Friday, killing one person and injuring two others, later registered a blood-alcohol level of 0.19 percent, police said.

Updated Slideshow: 1 Killed, 2 Injured When Officer Hits Motorcycles
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Before the crash, police said Bisard had taken his cruiser to the sheriff's garage for preventative maintenance and had driven his children to a soccer camp before coming to work.

Addiction therapists report that 10 percent of the population hides that they drink on the job.

"What perpetuates it is the drinker will maintain a sincere delusion about their drinking, that it's not a problem," Nick Sahaidachny with Valley Vista Health System told 6News' Stacia Matthews.

He said that in the workplace, alcoholism can show itself in increased absence and decreased productivity, while coworkers may also notice mood swings, anxiety and excuses for the behavior.

"These are all the many disguises of addiction that I see. It can be very distracting, and may miss the real issue of what's going on," Sahaidachny said.

As for how Bisard's co-workers didn't suspect he was drunk, Dr. Brent Furbee, a medical toxicologist with the Indiana Poison Center, said the point at which a person exhibits intoxication can vary.

He said can be different based on things such as weight, height, what kind of alcohol was consumed, how often the person usually drinks, how the body metabolizes alcohol and if the person ate before drinking.

Sahaidachny said co-workers who do find out about a person's drinking habit may be caught up into unwittingly helping an alcoholic deny there's a problem.

"The addict is so insidious and so slick and in many ways very crafty that friends, family and coworkers can be pulled into the dance," he said. "You don't have to diagnose this situation. You can leave that to us clinicians. But, certainly, you can identify problematic behavior in the workplace."

Bisard was charged with operating while under the influence causing death, a Class B felony; operating while under the influence causing death, a Class C felony; reckless homicide, a Class C felony; and four counts of operating while under the influence causing serious injury, Class C felonies.

Once Bisard is recommended for dismissal, a police merit board will decide if the officer should be terminated. They won't make that determination until all court proceedings are completed.