Jammers silence the alarm in a $1m Glendale burglary

A measured share. The fastest-growing characterisation is an insurer's assessment, not a count, and no party in the report publishes the number of jewelry burglaries in which a jammer was recovered. A count from the JSA or from law enforcement, in either direction, would settle whether this is a fast-growing tactic or a well-publicised one. A conviction rate in the Los Angeles case would also test how far the detection and evidence chain holds up.

A monitored intrusion system is two things: a panel that senses, and a path that tells someone. Most jewelry-store panels now report over a cellular link, because a cut phone line was the classic defeat and cellular removed it. A jammer attacks the path rather than the panel. It transmits noise across the radio bands the panel's cellular radio uses, so the panel can arm, sense a door or a vibration, and raise an internal condition that never reaches the central station. That is why the Glendale owner found his system still online: nothing had failed in the sense the panel understands, and nothing had been reported in the sense the owner needed. Detection inverts the problem. A jam detector does not restore the path; it listens for the signature of the noise and trips a zone on the panel, which can then be reported over whatever path still works. That is the reason the redundancy advice ranks above the detector in the report: a detector with one path left to shout down is still a detector with one path.

JCK's report was fetched directly at its own address, https://www.jckonline.com/editorial-article/jammers-holidays/, 200, and read as plain body text rather than through a summary. Its byline is Sam Cooley and its date, printed in the body, is 25 September 2026. The figures attributed to each named party were located in that text one at a time: Tyler Jagiello of Jewelers Mutual is the source of the fastest-growing characterisation, given by email; Mark Hillenburg of Digital Monitoring Products describes the flooding mechanism and the June 2025 Jam Alert launch; Christopher Geymuller of ProNet Security gives the antenna count, the 350-square-foot to 100,000-square-foot coverage span, the Dallas case and the multiple-paths advice; Scott Guginsky of the Jewelers' Security Alliance gives the TRTL-30x6 safe rating, the camera height, the 60-to-90-day retention advice and the seasonal exposures. Each of those attributions was checked against the sentence in the source that carries it, not assigned from memory of the piece. The violence share is not JCK's own figure in that article: the sentence carrying 16.9% and 27.1% is hyperlinked in the source to a second JCK article of 28 April 2026 on the Jewelers' Security Alliance 2025 Annual Crime Report, and that second page was fetched separately, 200, and read. It states that crimes involving violence against jewelry industry employees rose from 16.9% in 2024 to 27.1% in 2025, and it is the source cited here for those two numbers. The same report's $144.7m of total dollar losses, up 1.5% from $142.5m, and its count of 1,233 crimes against US jewelry firms in 2025, down from 1,420, are in the table because this paper published both on 3 August 2026 from the same annual report; they are context, and the third source listed is that earlier article. The 27.1% share itself has not appeared in this paper before. The archive was checked by opening every hit rather than counting: a search for jammer returns nothing across the site, so the tactic is new here. A search for the Jewelers' Security Alliance returns two articles, both opened: the 3 August piece on the 2025 annual report, which covers the 2025 calendar year and carries the loss and crime-count totals, and an 18 September piece on Stuller's share-of-doors presentation, which quotes Guginsky on an unrelated point. Under the period rule the new item is a September 2026 trade report on a tactic, and the archived item is an April 2026 report on a 2025 dataset, so this advances rather than repeats, and the overlap is confined to the two 2025 totals, which are labelled as previously published. No direct quotation is used in this article; every attributed statement in the source is paraphrased with the speaker's name attached, and the quote count for this piece is zero. The $3m figure the jeweler gives in his closing quotation is not printed as a loss figure because it conflicts with the report's own more-than-$1m inventory line; the conflict is disclosed in the table note instead of being resolved by this desk.

• Signal Jammers Silence Store Alarms Ahead of Holidays, Security Experts Say, JCK (Sam Cooley) ↗
• 2025 Jewelry Crimes Down But Total Dollar Losses Rise, JCK (Karen Dybis), on the JSA 2025 Annual Crime Report ↗
• Shoplifting falls 12.4%, and the fraud desk fills up, Carat Capital ↗