An unknown number of guns are being built with the mechanisms, causing problems for the police and ATF officials. Photo: An ATF agent holds a generic unfinished receiver, back, and one that has been manufactured, front, at an ATF field office in Washington, on May 06, 2014. The ATF is trying to crack down on the trade in the makeshift guns by targeting shops and individuals who offer to turn the unfinished receivers into functional pieces for firearms. (Photo by Bill O'Leary/The Washington Post)

The figure of an eight-year-old boy is seen inside a suitcase on a Spanish civil guard scanner screen at the border between Morocco and Spain's north african enclave Ceuta, Spain in this handout photo released May 8, 2015. A 19-year-old woman was arrested May 7, 2015 for the attempted smuggling of the boy, who was checked by medics and handed over to juvenile prosecutors office, according to authorities. (Photo by Reuters/Ministerio Del Interior)

Adrienne Sipe (L) and Brooke Gilliam of Washington D.C. leap off a snow podium they made near the U.S. Capitol in Washington February 13, 2014. A deadly and intensifying winter storm packing heavy snow, sleet and rain pelted a huge swath of the U.S. East Coast on Thursday, grounding flights and shuttering schools and government offices. (Photo by Kevin Lamarque/Reuters)

Nasar, an Arabian horse, stands in the office of doctor Stephanie Arndt at her home on February 19, 2014 in Holt, Germany. Fearing for the horse's safety, Mrs. Arndt brought the horse into her house during the Xaver heavy storm back in December, and the horse now wanders through the house daily, inspecting details and looking for snacks. Mrs. Arndt says she doesn't mind, and though the horse never spends the night, it does occasionally take a nap in the house. (Photo by Patrick Lux/Getty Images)

A Belarusian law enforcement officer approaches women, who react while sitting on the pavement during a rally of opposition supporters following the presidential election in Minsk, Belarus on August 10, 2020. Belarusian police clashed with protesters on Monday after the opposition accused President Alexander Lukashenko of rigging his re-election victory amid a chorus of criticism from Western leaders. (Photo by Vasily Fedosenko/Reuters)

Police officers in action during the eviction of the “Liebig 34” squat, at Friedrichshain district in Berlin, Germany, 09 October 2020. A local court ruled in favor of the eviction of the self-declared “anarcha-queer feminist” house project at Liebig street 34 in June 2020. The house project is considered a stronghold of the left-wing scene in the German capital. (Photo by Filip Singer/EPA/EFE)

Police officers detain a Navalny supporter during a protest in St. Petersburg, Russia, Tuesday, February 2, 2021. A Moscow court has ordered Russian opposition leader Alexei Navalny to prison for more than 2 1/2 years on charges that he violated the terms of his probation while he was recuperating in Germany from nerve-agent poisoning. Navalny, who is the most prominent critic of President Vladimir Putin, had earlier denounced the proceedings as a vain attempt by the Kremlin to scare millions of Russians into submission. (Photo by Dmitri Lovetsky/AP Photo)

Supporters of Pakistan Tehreek-e-Insaf (PTI) party of Prime Minister Imran Khan shout slogans outside the Parliament House building in Islamabad on April 3, 2022. Pakistan will go to the polls to elect a new government within three months after Prime Minister Imran Khan foiled an attempt to boot him from office April 3 by getting the president to dissolve the national assembly. (Photo by Aamir Qureshi/AFP Photo)