Paris Williams burst into a northeast Houston laundromat in late 2016, pistol in hand, and fired into the air.

He wanted cash. Instead, the storekeeper dove for the ground, locking the door to the plexiglass-enforced area behind the cash register. Stymied, Williams, and his accomplice, Gabriel Howard, fled moments later.

They wore masks and left few clues. Years ago, that might well have been the end of the case, written off by overburdened investigators as yet another spasm of gun violence northeast of downtown.

This time, however, an officer picked up the forgotten bullet casing and gave it to evidence analysts to compare against a federal ballistics database called the National Integrated Ballistics Information Network, known as NIBIN. Soon they had a lead: the casing matched one from another shooting in a park the day before.

It was something to go on.

Two months later, the suspects were behind bars, nabbed by one of the 2,000 leads in Houston and southeast Texas that have generated more than 100 arrests since federal officials began pushing NIBIN for tackling repeat gun crime.

Even as Houston-area departments credit the ballistics database with leading to more arrests, however, the Bureau of Alcohol, Tobacco, Firearms and Explosives is still fighting to implement a nationwide gun-fighting strategy among the nation’s plethora of local and state law enforcement agencies and forensic labs.

At issue: laboratories that often take months to process data, supplying it on the eve of trial instead of during an active investigation; cash-strapped departments that don’t consider such testing part of a standard investigation or that balk at the effort needed to speed up testing; and investigators who believe focusing on minor gun crimes — those that don’t involve injuries or fatalities — hampers investigations into on more serious shootings.

“We're talking about directly focusing on people that are trigger pullers,” Fred Milanowski, Special Agent-in-Charge of ATF’s Houston Field Office said. “Those are the people we want out of our communities.”

Getting comfortable with a gun

Mounting evidence shows that a small portion of shooters commit an outsized portion of gun crimes.

“We know that when two shootings are tied together through NIBIN, there’s a 50 percent chance that guns are going to be used in another shooting in the next 90 days,” Milanowski said, citing a recent study from Rutgers University. “Once you're comfortable shooting, you’re going to continue to shoot.”

The ATF database allows firearms experts to match high-resolution photos of marks left on bullet casings after being fired. The guns' firing pins leave a mark unique to each gun, allowing investigators to connect casings fired at different shootings.

In Houston, those shootings take a notable toll: Firearms were used in more than 600 homicides and suicides in Harris County in 2017, and more guns are recovered in Houston — by far — than anywhere else in Texas.

The most recent federal data show law enforcement seized 7,398 firearms in Houston last year, more than all the guns collected in Dallas, San Antonio, and Fort Worth combined. After the laundromat shooting, forensic technicians imaged the casing Williams left behind, and entered it into the NIBIN database. That produced a match to the casing left at the park the previous day.

Using clues from those two shootings, investigators from a joint team of Houston police and federal agents ultimately tied the attempted robbery to Williams, 24, who had previously been arrested on burglary charges a year before.

A joint task force of Houston police officers and ATF agents used the NIBIN lead and other clues to bring him in and soon had a case against him.

Spotty implementation

The Bureau of Alcohol, Tobacco, Firearms and Explosives has spent years trying to convince local agencies to be more proactive in using the database, which is similar to other federal criminal databases of fingerprints and genetic material.

In years past, however, the agency weathered budget shortfalls, disinterested leadership and spotty implementation at the local level, all of which meant that the database was far less effective than it might have been.

ATF’s challenge has been to convince the nation’s fragmented law enforcement system — with more than 18,000 agencies across the country — to use NIBIN technology as part of a comprehensive effort to curb gun crime. In some states, those efforts have fallen woefully short: In Maryland, officials abandoned a separate ballistics imaging database that failed to produce results despite years of entries. Across the nation, meanwhile, just two states — Delaware and New Jersey — require law enforcement to use the technology.

Officials say they have renewed backing from the Department of Justice. The agency also received budget appropriations to place imaging machines in 25 more cities across the country. This summer, the agency implemented nationwide operating standards requiring partner agencies to perform and disseminate ballistic analysis within five days — or lose access to the database entirely.

In Texas, those efforts are starting to pay off, Milanowski said.

Where testing times at local forensic labs once routinely took as long as 180 days after a shooting — allowing cases to stagnate — technicians now perform analysis within three days.

Now, most labs across the region have cut that testing time to just a few days, a change officials say is critical to reducing gun crime. Matching those efforts across the region and elsewhere, the Department of Justice imposed guidelines requiring participating agencies to shorten testing times to just two days, a move experts say is critical to making the system actually work.

“There was such a time delay between when crimes occurred and hits came out,” said William King, a Sam Houston State University criminology professor who previously studied problems with NIBIN’s effectiveness. “Focusing on timeliness -- I’m glad ATF has pushed that.”

A team of about a dozen investigators from ATF, the Houston Police Department and the Harris County Sheriff’s Office took over investigations involving guns used in multiple incidents and funneled leads back to detectives.

“It’s not enough to get the evidence, to get the hit,” said Houston Police Chief Art Acevedo, whose department recently acquired its own ballistics imaging machine. “We have to make sure we’re aggressively following up on any hit we get on NIBIN. I think that’s something new for us, to be honest with you.”

Energizing investigators

HPD Assistant Chief Bobby Dobbins credited the system with helping HPD detectives generate dozens of leads in cases within city limits since 2016, as well as others in the county — and one as far away as Tulsa, Okla.

“It’s had a noticeable effect for our officers,” Dobbins said. “Now they look at it as a tool to reduce the crime in their areas, in a quicker response, so they’re excited to gather more evidence.”

North of Houston, the Montgomery County Sheriff’s Office obtained and began using its own NIBIN imaging machines in early August, rather than making weekly trips to Harris County’s lab. The department also recently changed policies to require deputies to submit ballistics evidence within 24 hours, with an overall goal of turning leads around within 72 hours.

“The quicker we can get the leads out the quicker we can get suspects off the street and hopefully prevent a gun crime,” Montgomery County Sheriff’s Lt. Scott Spencer said in an email.

Milanowski said ATF also hopes to place a ballistics imaging machine in the Rio Grande Valley, to help speed up gun investigations across South Texas.

Back at the laundromat

At Washateria 4 You, the scent of fresh laundry filled the air on a recent Monday as dryers whirled.

Sandra Nguyen, 50, counted out quarters behind the bulletproof plexiglass in the back of the business. She and her family have run the laundromat, a spartan shop three miles northeast of downtown, since 2001.

“It was really bad back then,” she said.

Her son, Kenny, an engineer, was working the Sunday — her one day off — when Williams and Howard burst into the laundromat.

They fired shots into the air, sending terrified customers scattering, then menaced the store clerk as he hid behind the bulletproof cubicle. When that failed to work, they fled.

Williams — the main shooter — was eventually sentenced to 45 years in prison for aggravated robbery and aggravated assault. Howard, his accomplice, received 10 years for aggravated robbery.

“They have to pay for what they did,” Nguyen said.

st.john.smith@chron.com