Police departments throughout the country are flush with cash provided by private donors, making it possible for precincts to acquire a vast array of new law enforcement equipment. From horses to surveillance cameras, agencies on both coasts have obtained the equipment in a way that allows them to subvert the normal legislative process at a time when questions over municipal militarization are getting louder.

When the Los Angeles Police Department in 2007 had its eye on new surveillance equipment capable of connecting traditional crime reports with information gleaned from security cameras and license plate-readers, Chief of Police William Bratton solicited the money from the Los Angeles Police Foundation. By taking his request to the private charity, Bratton, now commissioner of the New York City Police Department, avoided a potentially yearslong bureaucratic operation, including a public review of the surveillance equipment and possibly a lengthy bidding procedure. Skipping that approval process also made it easier for Bratton to avoid disclosing that the surveillance was originally developed by Palantir, an intelligence startup partly funded by the CIA.

All the details are included in an extensive ProPublica investigation that explains not only how the increasingly militarized police forces who patrol American streets acquired their arms but also how little oversight there is to safeguard the public's interest in such transactions. It also comes after months of protests in Ferguson, Missouri, over the death of Michael Brown, a young African-American man fatally shot by a local officer. The Ferguson police, under the national spotlight, responded to the demonstrations with automatic weapons, sniper rifles, mine-resistant ambush vehicles and other equipment designed for the battlefield.

Along with Los Angeles, police in New York City, Atlanta and Oakland have also relied on private foundations to pay for various equipment, with advocates saying the funds are necessary after the budgetary constraints that have been imposed in recent years. Documents obtained by ProPublica indicate that private donations were used to fulfill payments for things such as former NYPD Commissioner Ray Kelly's membership fees for the private Harvard Club, whereas in 2013 nearly half of the $6.5 million in private funds went toward the department's “technology campaign.”

Similarly, the city of Atlanta used money to install 12,000 new surveillance cameras this year, and the LAPD spent more than $650,000 over 2010-2011 on counterterrorism surveillance. The next year, the LAPD dedicated $25,000 to upgrade its Stingray surveillance equipment, originally designed to combat terrorism, to monitor drug transaction's in the city's Skid Row neighborhood.

“I think we all see ourselves as part of a larger puzzle, which is making sure that Los Angeles has a world-class police department, and we're just the private funding source,” Cecilia Glassman, executive director of a police charity, told ProPublica.

Others were less optimistic, with critics suggesting that a growing reliance on non-tax dollars could reduce a police department's accountability to the public that it's supposed to protect and serve.

“At least with public contracts and spending there's a facade of transparency and accountability,” said Ana Muniz, a researcher who's studied the LAPD's donations. “With private partnerships, with private technology, there's nothing.”