(CBS) - Twice before he shot and killed 12 people in a rampage at the Washington Navy Yard on Sept. 16, Aaron Alexis was arrested for discharging a firearm - once in his Ft. Worth apartment, and once outside his grandmother's home in Seattle. Neither time was he prosecuted for a crime. Now, the question is why not.
According to the Seattle Police Department(SPD) report, on May 7, 2004, Alexis allegedly used a Glock .45 to shoot out the tires of a construction vehicle parked outside the home of a neighbor. After being arrested, Alexis told police he'd fired the gun in an anger-fueled "black out."
According to the Seattle Times, Alexis was booked on investigation of malicious mischief, but what happened next is less clear. In a statement released Sept. 16 shortly after the Navy Yard massacre, the SPD says the case was referred to the Seattle Municipal Court for prosecution, but a court spokesperson says they never received the case. In addition, spokespeople for both the Municipal Court and the City Attorney's office said that, typically, such a case would be referred to the City Attorney's office. But according to the City Attorney's office, they did not receive a referral for Alexis' case. Because of this, the Times reports, when Alexis appeared in court the next month, the charges were dropped.
Asked why the case was referred to the Municipal Court instead of the City Attorney's office, a Seattle PD spokesman told CBS News' Crimesider, "I don't know."
In Texas, the situation appears to have been more straightforward. According to the the Ft. Worth Police Department report, Alexis's neighbor - who told police she had been confronted multiple times by Alexis over noise in her apartment - called police on Sept 4, 2010 after she heard a "pop," saw smoke, and then noticed a hole in the floor a few feet from where she was sitting.
Police interviewed Alexis who said he had been cleaning his gun when it accidentally went off. According to a summary narrative of the incident, the officer who spoke with Alexis saw that his gun was taken apart and sitting next to a gun cleaning kit. He booked Alexis on suspicion of recklessly discharging a firearm, but according to a statement from the Tarrant County District Attorney's office, "After reviewing the facts presented by the police department, it was determined that the elements constituting recklessness under Texas law were not present and a case was not filed."
Hindsight is 20/20, of course, but David Kopel of the University of Denver's School of Law thinks both the Texas and Washington shootings "weren't taken seriously enough." Especially, he says, the Ft. Worth case: "The apartment shooting was almost a reckless homicide, and should have been prosecuted."
Adam Winkler of UCLA's School of Law told Crimesider that across the country, "seemingly victimless crimes" like the ones Alexis was arrested for are not a priority for prosecutors.
"Prosecutors are reluctant to press charges for minor gun crimes because it can be difficult to win convictions and resources are scarce," said Winkler. But, he warns, "minor gun crimes are a sign of trouble ahead."
David Webster, the Director of the Johns Hopkins Center for Gun Policy and Research, agrees, calling minor gun offenses "red flags" for future criminal activity.
Much has been made about research indicating that federal prosecutions of gun crimes have been falling since about 2004, but experts say good data on state and local prosecutions of gun crimes is harder to come by because the laws are different across the country.
Webster told Crimesider that there are several reasons why crimes like those Alexis was arrested for are not priorities for prosecution. Lack of resources is one. Another is disparity in jurisdictional crime rates, which Webster says means that in some low-crime areas a minor gun crime might be charged, but in another the prosecutor might feel she has "bigger fish to fry."
And that leads to the third reason. Unlike drug offenses, which often carry stiff punishments, Webster says long sentences are rare in minor gun crimes and that prosecutors looking to "earn their stripes" focus on cases where they can win convictions that result in long prison terms.
Finally, there is the wide variation in state gun laws. As an example, Webster points to the Plaxico Burress case. In 2008, the NFL player accidentally shot himself in the leg in a Manhattan club with a gun that wasn't licensed in the state.
"That same case in Virginia or Texas he would have gotten a slap on the wrist - community service or probation," said Webster.
But in New York City, Burress was sentenced to two years in jail.
Whether Alexis would have been convicted had he been charged in either the Ft. Worth or Seattle shooting incident, we will never know. But what we do know is that Alexis bought the shotgun he used in the Navy Yard shooting in Virginia, and according to that state's law, you can be barred from purchasing a firearm if you were "convicted in any court of a misdemeanor crime punishable by more than 2 years..."