Each week, the editors at The Post's Investigations blog comb through in-depth and investigative reports from news outlets across the country and select the most notable projects of the week.

This week's top picks:

Profiting On 'Pollution Credits'

Garbage dumps nationwide are reaping big rewards off the sale of "carbon credits" for environmental programs they already had in place, The Wall Street Journal's Jeffrey Ball reports.

The Journal found that for years landfills have made profits by collecting methane from rotting trash and selling it as fuel.

But last year, landfill owners found that a new government program that pays companies to cut their greenhouse-gas emissions would allow them to earn extra cash for something they've already been doing.

The Underground Tobacco Trade

From underground factories in China to the lawless border lands of northwest Pakistan and southeast Paraguay, the booming global trade of smuggled cigarettes has shifted into a worldwide business, according to a six-part investigative series by The Center for Public Integrity's International Consortium of Investigative Journalists.

Using reporters in more than a dozen countries, The Center for Public Integrity found that contraband shipments account for nearly 11 percent of all cigarette sales; Europe is being flooded by smuggled Russian cigarettes worth at least $1 billion a year; and the story of one of America's biggest ever cigarette smuggling rings -- a racket that spanned three continents and six states and moved as many as a half-billion contraband cigarettes across the United States.

Whistleblower's Death Sparks Reforms

When Rachel Morningstar Hoffman agreed to help police catch some drug dealers, she just wanted some extra money to attend culinary school, the Tallahassee (Fla.) Democrat found.

Three weeks later, she was dead, killed in a botched drug sting in May.

As a result of her death, a police investigator was fired and the Democrat has waged a legal battle over sealing evidence in the case. Hoffman's family and the Tallahassee police chief are supporting a new law, dubbed Rachel's Law, that would include more careful screening and provide protections for confidential informants.