The evidence piles up.

A man dumped furniture, closet doors, and assorted construction debris in Fairmount Park, saying he was following his boss’ orders. Two people drove from New Jersey to dump in Kensington. A hauling company, paid to dispose of trash legally, dumped it on Erie Avenue.

Some people dump in the middle of the night. Some dump in the middle of the day. Some dump in secluded wooded areas. And some “just dump in the middle of the street,” said Philadelphia Police Detective Mark Flacco of the environmental crimes unit.

“There’s dumping all over the city. It’s really, really bad,” he said. “There are streets you can’t even drive down, they’re so filled with stuff."

In the fight to rid the city of its “Filthadelphia” reputation, the city is turning to a new law enforcement tool: cameras specifically set up to catch dumpers.

In December it announced the installation of 15 cameras. That number will grow to 50 by the spring. And by the end of the year, officials plan to have 100 throughout the city.

Philadelphia, which spends millions annually cleaning up illegally dumped debris, is counting on the cameras to help deter or prosecute dumpers. The cameras supplement ones used by police. The city joins communities across the country combating persistent piles of filth with photographic evidence.

Houston, a city of 2.3 million, began its camera program in 2015. It had a bit of a rough start: Some of the first cameras got shot out.

Now, they are sleeker and better hidden, and the city has roughly 100 of them. “In certain areas, that’s not enough," said Houston Council member Jerry Davis, who said the bulk of his constituents complain about dumping. He said there will never be enough funding or people to monitor video to put cameras at every dumping site.

Two Bucks County municipalities that are renting cameras through the nonprofit Keep Pennsylvania Beautiful told the organization they want to keep their efforts quiet to catch dumpers off guard.

Allentown, Pittsburgh, Camden, and Norwalk, Conn., are among the cities that use illegal-dumping cameras. Reading started a pilot program in August and wants to expand it. Atlanta began one last month.

Cities and community groups across the country agree that cameras aren’t a panacea but a tool in cities’ toolboxes, which include public education campaigns, the promotion of legal dumping sites, and bulk waste drop-offs and pickups. And the cameras don’t work without arrests and prosecutions. The camera program is the latest initiative to curb illegal dumping, in addition to increased penalties, and targeted “litter enforcement corridors.”

And then there’s the inevitable: When cameras go up, “you’ll find it’s human nature [people] will go somewhere else and dump," said David Shockley, a Norwalk city official.

Philadelphia officials plan to place cameras in dumping hot spots, and some are already up along Wyoming Avenue and Courtland Streets and elsewhere.

As technology has advanced, so has the quality of surveillance cameras’ photos and video.

Philadelphia’s $4,000 cameras detect motion, rotate, zoom, and can take clear images at night. Streets Department employees monitor the cameras and 311 tips and refer cases of dumping to police. When officers know when and where dumping occurs, they sometimes lie in wait to catch people in the act.

Since 2013, Keep Pennsylvania Beautiful has rented out roughly 40 sets of cameras through its state-funded program. In five years, 65 people have been convicted and municipalities and state agencies have collected more than $20,000 in fines and court costs.

Often, the litter problem on a block is so bad that a community thinks many people are dumping, but in reality, it may be one or two, said Robert Dubas, a program coordinator for the nonprofit. If those people are prosecuted, “sometimes that can be enough to help an area,” he said.

The organization has shipped cameras to Aurora, Colo., and is in talks with Durham, N.C.

Camden started using cameras four years ago and just replaced them with four high-tech models, which cost $7,000 each, a few weeks ago. City officials plan to assess the cameras’ success and, potentially, to buy more. Keith Walker, the city’s Public Works director, said prosecuting people using cameras helped stop dumping at the site of the former Camden Labs building, a long-trashed area that the city is turning into a park.

But the cameras don’t work everywhere. A nonprofit that manages a 30-square-mile watershed across Philadelphia and Montgomery County used cameras along an isolated, winding stretch of road that leads into Tacony Creek Park. Although the group placed cameras strategically, dumping always happened out of frame. After six months, people found and destroyed the cameras, said Robin Irizarry, Philadelphia watershed coordinator for the Tookany/Tacony-Frankford Watershed Partnership.

Oakland, Calif., a city of about 420,000, has four illegal-dumping cameras. Officials said last February that their program, a few years old, was not working and not worth expanding. The city also has a strong Privacy Advisory Commission and residents fear police surveillance.

Allentown officials said cameras in use since 2000 have helped decrease illegal dumping. Although Allentown issued 52 illegal-dumping citations from 2016 to 2018, most came from identifying offenders from material they dumped, not from the city’s cameras.

"We’ll try anything to cut back on illegal dumping and the costs that are involved in cleaning these places up,” said Tom Harper, SWEEP manager for Allentown.

He said the additional cameras in Philadelphia mean “a hundred more eyes” on the dumping problem.