WASHINGTON — Police racing to solve the Boston Marathon bombing were prevented from using existing technology to identify the source of the black powder in the explosives that killed three and injured more than 260. They've also been unable to trace the gun used to kill a police officer.
In both cases an urgent investigation - where more lives could have been in danger - was hindered because of a decades- long campaign by the National Rifle Association and its allies in Congress to prevent the collection of data about guns and ammunition, former law enforcement officials say.
Heeding an NRA argument that such measures are costly and ineffective, Congress has resisted mandating chemical "tags" in gunpowder, blocked efforts to require microscopic serial numbers in firearms, and banned health authorities from analyzing records on gun injuries. The result, say officials and gun-control advocates, is that crimes go unsolved and a true picture of the extent of firearms violence is lacking.
"It's been this 30-year battle," said Josh Horwitz, executive director of the nonprofit Coalition to Stop Gun Violence, with "the NRA always being on the side about making it harder to get information about guns used in crimes."
The investigation of the Boston bombings is the latest example of how the firearms lobby has helped weaken U.S. laws governing the collection and distribution of information vital to tracking weapons and spotting gun trafficking.
The campaign includes a 1986 package of NRA-backed legislation that called for curbs on dealer inspections and extends to prohibitions on the government requiring dealers to keep sales inventories.
A 2012 study by Johns Hopkins University's Center for Gun Policy and Research reported that some of the measures led to a surge in gun trafficking by at least one supplier of firearms used in crimes.
The NRA, which claims 5 million members, maintains that keeping gun records is the first step toward a national registry and possible confiscation. During a convention last week in Houston, Wayne LaPierre, executive vice president of the Fairfax, Va.-based group, repeated a longstanding criticism that current laws must be enforced and called for rebuilding "our broken mental health system."
The NRA didn't respond to a request for comment on this story.
Dave Workman, a gun-rights advocate for the Second Amendment Foundation, said the data would be misused.
"Data would be accessed not for criminal investigations but for political purposes such as launching junk lawsuits against gun dealers," said Workman, who edits a magazine for the Bellevue, Wash.-based group.
A review of federal measures designed to empower law enforcement shows the extent to which the authorities have been impeded from carrying out current laws.
"They're saying 'Enforce the laws on the books,' but if you throw obstacles at us in trying to do so, you're setting us up for failure," said Joseph Bielevicz, a Pittsburgh police detective who came to Washington in March to testify in favor of expanded background checks.
In the April 15 Boston bombing, a manhunt for the killers that lasted days could have taken just hours had the explosives fragments littering the scene contained taggants, law enforcement veterans say. Authorities may never be able to track the gun used to kill a transit police officer because its external identification number was worn down.
"Just imagine if, the day of the bombing, there were these taggants all over the scene and law enforcement could immediately trace it," said David Chipman, who worked for the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives for 25 years and advocates for tougher laws. "Any of these things that allow law enforcement to trace these items have been thwarted."
ATF officials declined to comment. "We enforce the laws as they are written," spokeswoman Donna Sellers said.
Much of the erosion has taken place largely out of sight in the form of attachments, called "riders," to annual appropriations bills that fund the U.S. government.
In 2004, a package of NRA-backed riders aimed at limiting the ATF's ability to share data found at crime scenes passed after some municipalities had begun to file lawsuits against gun makers, according to a March report by the Center for American Progress. The Washington research group is aligned with Democrats.
"The NRA approached this in a very clever fashion where they're getting their Congress members to attach them to must- pass bills that don't get much scrutiny," said Mark Jones, a retired ATF supervisory agent who favors stricter gun laws.
After the 1995 Oklahoma City bombing, President Bill Clinton's attempt to include chemical identifiers in bomb materials was scuttled by NRA opposition, according to Robert Spitzer, an author of four books on the history of gun control.
In Boston, investigators "got lucky" when a New Hampshire fireworks dealer came forward with sales records of bomb materials, said Chipman, who now advises Mayors Against Illegal Guns, which advocates for more controls. The group is co-chaired by New York Mayor Michael Bloomberg, the majority owner of Bloomberg LP, the parent of Bloomberg News.
According to a 1999 NRA fact sheet, taggants are "unfeasible and of uncertain value," while an effective system and the associated record-keeping "would incur significant costs." It cites a 1996 National Research Council report finding that black and smokeless powder is responsible for only a small number of deaths each year.
Similarly, ATF has proposed encoding guns with microscopic serial numbers because it's a common practice for criminals to grind down external serial numbers.
Even if Congress required taggants and microscopic serial numbers, gun-lobby pressure has prevented proper record- keeping and gun-data analysis, Spitzer said. Clinton failed in his push to require gun and explosives dealers to keep a regular inventory of their products and where they were sold.
"You still run into the main problem," which is the lack of a paper trail, Jones said.
An NRA newsletter in March said the government was waging an "all-out war" on gun rights, including plans to create a national registry, though the ATF is barred from creating a centralized database of gun-sales records.
Federally licensed firearms dealers are required to maintain sales records. The ATF also receives an average of 1.3 million records each month from dealers who go out of business, the Center for American Progress report says. It keeps them in boxes in warehouses or on microfiche because agents are barred from keying the information into an electronic system.
ATF agents often sift through hundreds of thousands of slips of paper, make numerous phone calls to the manufacturer and retailers who first sold a weapon, and then to gun dealers who maintain background-check records of gun purchases, Jones said. A firearms trace can take days, or even weeks.
"People are flabbergasted when you start talking about it," he said. "We have to use 19th-century technology to track guns."
Law enforcement's paperwork troubles were compounded in 2004, when Congress approved a rider that hampers the ability to identify straw purchasers, or individuals who buy guns on behalf of people prohibited from owning them.
The measure stipulates that the FBI may retain records for only 24 hours of individuals who have passed background reviews under the National Instant Criminal Background Check System. That hurts the bureau's ability to track sales patterns crucial to identifying straw purchasing and gun trafficking.
When the database was created, the FBI kept sales records for six months. The Johns Hopkins's study found that the effect of these riders was a surge in gun trafficking.
For instance, one of the nation's leading suppliers of guns used in crimes was Badger Guns & Ammo near Milwaukee, a retailer whose license was revoked in 2011. In 1999, Badger sold more guns that were later recovered at crime scenes than any other supplier. After passage of the amendments, the number of Badger guns found at crime scenes increased by 204 percent, according to the study.
A leading sponsor of the amendments was former Rep. Todd Tiahrt, R-Kansas, now a business consultant, who said the riders are being politicized.
"It doesn't tie police officers' hands at all," Tiahrt said in an interview. "The people that are really after all this stuff are people that are just pursuing more gun control," he said, citing President Obama's efforts to require dealers to keep inventory records.
Tiahrt said curbs on inventory requirements and on government audits were crafted in response to "excessive" inspections. "We just brought it back to reasonable limits," he said.
In 2004, the gun lobby backed an amendment to prohibit the ATF from requiring dealers to conduct annual inventories. In 2011, the bureau found that almost 18,500 guns were unaccounted for during the course of 13,100 compliance inspections, according to the ATF.
"Everyone from Wal-Mart down to the corner grocery store understands how important it is to know where your stuff is," Jones said. "The firearms industry is the one industry in our country that doesn't seem to think it's a good idea."
Obama has fought the limits on law enforcement. In the latest budget plan he submitted to Congress, he called for the removal of four of 15 of the gun-related riders that have passed Congress, according to Arkadi Gerney, an author of the Center for American Progress report.
In May of last year, he threatened to veto an appropriations bill because of a rider that would have prohibited the ATF from requiring dealers in four border states to report the sale of multiple rifles or shotguns to a single individual. The policy was intended to fight gun trafficking. The measure was removed.
Another obstacle for law enforcement is that the public is largely ignorant of the implications of gun violence.
In 1996, then-Rep. Jay Dickey, R-Ark., attached an amendment forbidding the Centers for Disease Control from conducting research to "advocate or promote gun control." In 2012, another amendment extended the gun-research prohibition to the National Institutes of Health.
The NRA said gun violence is a law-enforcement issue and that research institutions shouldn't be part of the debate. In the ensuing years, CDC funding for firearm-injury prevention has fallen by 96 percent, according to a study by Mayors Against Illegal Guns.
"It enforces relative ignorance on the whole consequences of guns," Spitzer said.