Two major providers of police body-worn cameras have become embroiled in a patent battle.

Kansas-based Digital Ally sued Arizona-based Taser International late last week. The company accused Taser's Axon Flex body cameras of infringing its US Patent No. 8,781,292. The patent describes linking together a body-worn camera, a vehicle-based camera, and a "managing apparatus" that communicate with each other.

The lawsuit was filed just after the Digital Ally patent overcame Taser's legal challenge at the US Patent and Trademark Office.

"Given our investment and superior implementation of the technology and its importance to the safety of officers and our communities, Digital Ally could not sit silently while TASER misappropriated our intellectual property and used our very own inventions to compete against us," Digital Ally CEO Stanton Ross said in a statement.

Digital Ally produces body and vehicle-mounted cameras for law enforcement and security personnel as well as video systems for big clients like the State of New York. Its total sales for the first nine months of 2015 were just under $15 million. The company still experienced a $2.1 million operating loss during that period.

Taser is mostly known for selling its electronic weapons, but it also sells Axon cameras and video through its Evidence.com service. Taser's Axon segment had $26.1 million in revenue for the first nine months of 2015. While Taser overall is profitable, its Axon segment experienced a net loss of $17.2 million during that period.

In its complaint (PDF) filed in federal court in Kansas, Digital Ally says it was first to recognize the "severe limitation" in the body-cam market. "[E]xisting devices required manual activation and manual management of multiple devices," the company's lawyers state in the complaint. "Requiring officers to manually manage their entire ecosystem of recording devices was distracting and particularly undesirable in dangerous situations."

The lawsuit also notes that Digital Ally is about to receive a related patent based on a pending patent application. Digital Ally says the second patent has been granted but is awaiting issuance by the patent office, and it intends to add this to its lawsuit once the patent is issued.

Use of body-worn cameras by police has grown quickly since controversial police actions and widespread demonstrations everywhere from Ferguson, Missouri, to New York City last year. As its business grows accordingly, Digital Ally has scored contracts with Philadelphia's transit police and the Santa Fe Police Department among others.

Meanwhile, Taser is poised for massive growth in its body-cam segment, including a potential $57 million contract to equip all 7,000 uniformed Los Angeles Police Department officers by the end of 2016. If the LA City Council approves the purchase, it will be the largest purchase of police body cameras in the US to date, according to IBT.

"Taser has been very successful in defending litigation and we have prevailed in all previous patent lawsuits with competitors," Taser General Counsel Doug Klint said in a statement. "We believe we will prevail in this litigation as well."

The statement also said that Taser conducts "extensive prior art and patent searches" as it develops its products, and points out that the '292 patent claims were narrowed during reexamination. The Digital Ally lawsuit is "frivolous and agregious," Taser said.