Michael Bell is a retired lieutenant colonel in the U.S. Air Force. His son Michael Jr. was killed in 2004 in a police shooting in Kenosha, Wis.

My 21-year-old son was killed by a cop in 2004.

It happened outside his home late at night. An officer pulled up behind Michael’s parked car and said that he had failed to make a complete stop at a stop sign. Michael denied the accusations and refused a sobriety test, leading to a scuffle in which the officers Tasered him and shoved him against his vehicle. Michael then ran up his driveway, where officers held him over another car.

One officer shouted that Michael had grabbed his holstered gun, although this was probably mistaken for his holster being caught on a car mirror. A different officer shot Michael in the head at point-blank range in front of multiple witnesses — including his mother and sister.

The police department immediately launched an investigation. Within two days, the shooting was ruled justified. Investigators cleared the officers of any wrongdoing before forensic reports, lab work or all eyewitness accounts were available. The officers later received awards for dedicated service in connection with the incident.

Only when I hired my own investigators did we learn of evidence and witness testimony that suggested the officers had made a mistake. Such one-sided, cursory investigations are the norm in our state. Our research, which examined a century of records, failed to discover a single case of a Wisconsin police department finding an officer’s shooting “unjustified.”

Pro forma internal investigations that reach a predetermined “justified” verdict seriously harm citizens and police. They fuel animosity toward officers, most of whom are brave and honorable public servants. To improve cop-community relations, departments should bring in outside, impartial investigators to scrutinize shootings.

Run-ins with police end in tragedy far too often. Last year, officers shot and killed nearly 1,000 people. About a third of all fatal police shootings are considered questionable. Unfortunately, police investigators rarely examine fatal incidents with critical eyes.

Take the well-known case of Staten Island resident Eric Garner, who died in July 2014 after a police officer put him in a chokehold — a banned police maneuver in New York. The NYPD’s incident report neglected to mention the chokehold and said that Garner had never been “in great distress.”

A video taken by a private citizen contradicted the report. The recording showed Garner repeatedly pleading, “I can’t breathe.”

As a retired lieutenant colonel for the U.S. Air Force who flew support missions in Iraq, Bosnia and Afghanistan, I know what it’s like to make snap judgments in dangerous, high-stress situations.

Aviation, like police work, is a high-stakes, high-speed field. Mistakes happen. But when something goes wrong in the air, the National Transportation Safety Board — an external investigative body — aims to learn from those mistakes. The agency brings in unbiased experts to analyze accidents and gather facts. The NTSB then issues recommendations for measures to prevent further incidents. Those go to the Federal Aviation Administration, which may issue new regulations. The FAA also notifies the aviation community about NTSB findings and tracks groups that adopt the board’s recommendations.

These efforts are geared toward creating positive change, not assigning blame.

Consequently, air travel has become the safest mode of modern transportation. No deaths were reported on commercial jets in 2017. In fact, people are three times more likely to die from choking on food than traveling by airplane.

Our communities would be much safer and more trusting if police forces adopted the aviation model and brought in external expert investigators after each officer-involved shooting.

It’s common sense to bring in unbiased investigators to examine any serious incident. If a pro football player were suspected of taking steroids, would his own teammates be allowed to conduct an in-depth investigation and assign punishment? Of course not.

Just as important, investigators’ findings must be shared with police forces nationwide. The government should also release recommendations about how to avoid similar mistakes in the future, and track law enforcement departments that implement those recommendations.

Ten years after Michael was shot, Wisconsin became the first state in the nation to pass a law requiring external experts to investigate any case in which a police officer is involved in a death. Implementing similar reforms on a wider scale would prevent civilian casualties — and save officers’ lives. In 2016, a year featuring several high-profile deaths at the hands of police, 21 officers were killed in ambushes. That’s the highest tally in more than two decades. In some recent cases, the perpetrators were seeking revenge for the death of Eric Garner and similarly mishandled cases.

I recognize that the officers involved in Michael’s death made a mistake. I'm not angry at them. But I am ready to see this broken system change.