Taser International, which manufactures and sells police tools like stun guns and body cameras, has financial ties to police chiefs whose departments have purchased the devices, raising concerns about conflicts of interest between the company and the law enforcement agencies.

Taser has reportedly covered international airfare and hotels for police chiefs, and taken on recently retired chiefs as consultants, on many occasions directly after their departments signed contracts with the company to purchase their cameras, video storage, and other products, which can cost millions. Other chiefs have endorsed the company in speaking engagements at promotional conferences.

According to the Associated Press, a police chief in Fort Worth, Texas who had pushed for a Taser contract in his department wrote to a company representative in an email, "Someone should give me a raise."

While the demand for body cameras among law enforcement has risen in the wake of the high-profile police killings of unarmed citizens, critics are noting the potential for biased dealings when police chiefs profit off of private companies.

For example, the Salt Lake City police department used surplus funds to purchase 295 body cameras, which allowed them to bypass standard approval procedures with the city council, according to the AP. The department also refused to disclose how much it had spent on that equipment and ignored a month-old public records request.

"Department heads need to be very careful to avoid that type of appearance of an endorsement in a for-profit setting," Salt Lake City councilman Charlie Luke told AP.

In October, President Barack Obama responded to the outcry over the Pentagon's controversial 1033 program, which redistributes surplus military supplies to police forces, by releasing a 19-page report Federal Support for Local Law Enforcement Acquisition.

As Nadia Kayyali, a member of the activism team at the Electronic Frontier Foundation, pointed out at the time,"the President's review broadly overlooks surveillance technology. But the same DHS money that funds armored vehicles and night vision goggles funds intelligence gathering at the local level through fusion centers and drones, and events like Urban Shield, a 4 day long event that featured "preparedness" exercises as well as a marketplace of military and surveillance technology.