SILVER SPRING, Md. – A man who railed against the Discovery Channel’s environmental programming for years burst into the company’s headquarters with at least one explosive device strapped to his body Wednesday and took three people hostage at gunpoint before police shot him to death, officials said.

The hostages – two Discovery Communications employees and a security guard – were unhurt after the four-hour standoff.

An explosive device on the gunman’s body detonated when police shot him, Montgomery County Police Chief Thomas Manger said. Police were trying to determine whether two boxes and two backpacks the gunman had also contained explosives.

New TB test touted for speed, accuracy

Scientists are reporting a major advance in diagnosing tuberculosis: A new test can reveal in less than two hours, with high accuracy, whether someone has the disease and if it’s resistant to the main drug for treating it.

The test could revolutionize TB care and replace the 125-year-old process used now, which is slow and misses more than half of all cases, experts say. A better test would be a powerful tool to curb TB in poor countries.

The new test requires only 15 minutes of manual labor, for taking the mucus sample, mixing it with chemicals and putting it in a cartridge. A machine amplifies the DNA in the sample and checks for bits of bacterial genes.

The test successfully identified 98 percent of all confirmed TB cases and 98 percent of ones resistant to rifampin, one of the top drugs to treat the disease.

Report: Big drop in illegal immigration

The number of illegal immigrants entering the United States has plunged by almost two-thirds in the past decade, a dramatic shift after years of growth in the population, according to a new report by the Pew Hispanic Center.

Between 2000 and 2005, an average of 850,000 people a year entered the United States without authorization, according to the report released Wednesday. As the economy plunged into recession between 2007 and 2009, that number fell to 300,000.

The drop-off has contributed to an 8 percent decrease in the estimated number of illegal immigrants living in the United States, from a peak of 12 million in 2007 to 11.1 million in 2009, the report said. Of the 11.1 million, 8.9 million came from Mexico and other parts of Latin America.

Owner turns her ire on piece’s co-owner

First it was a curious tale of a $1.3 million painting a middleman said he drunkenly lost while trying to help a friend sell it.

Now a part owner of the canvas identified its co-owner as an admitted art thief, her lawyer said.

Kristyn Trudgeon sued the middleman in New York this week. But attorney Max Di Fabio said she was withdrawing the lawsuit after realizing Wednesday upon seeing a prison mug shot that co-owner Thomas Doyle was the same man who pleaded guilty in 2007 to stealing a $600,000 Edgar Degas sculpture from a wealthy collector. Doyle, whose record also includes a stint in federal prison for a $200,000 jewelry swindle in Tennessee, was paroled in December, records show.

Trudgeon is “exploring potential legal remedies,” Di Fabio said. He declined to say how Trudgeon and Doyle knew each other and acquired the portrait – Jean-Baptiste-Camille Corot’s circa 1857 “Portrait of a Girl” – and whether it was insured.

Diet pill questioned by medical journal

Editors of the New England Journal of Medicine call Meridia “another flawed diet pill” and question whether it should stay on the market as a study shows it raises the risk of heart attack and stroke in some people.

The editorial in today’s issue comes two weeks before government advisers review the prescription drug. In January, U.S. drug regulators strengthened existing warnings that the appetite suppressant should not be used by those with a history of heart trouble.

The latest study showed weight loss with Meridia was minimal, it didn’t improve cardiovascular health, and those with heart disease fared worse.