Three university researchers working on medical technology are facing federal charges -- and up to 20 years in prison if convicted -- for allegedly taking Chinese money for their U.S.-funded research, according to federal authorities.

Damage assessments show that the Oklahoma tornado was an EF5 -- meaning it had winds of 200 mph or greater.

The National Weather Service said on Tuesday that the tornado was a category EF5, the most powerful category of tornado.    

Debt-laden businesses make decisions out of desperation. So cut up the credit cards and use these four strategies instead.

Assault prevention workers exempt fom furloughs.

The Bank of Japan on Wednesday decided to keep monetary policy on hold, but one board member tried unsuccessfully to loosen the central bank's commitment to achieving its inflation target.

POLITICO Pro Report: The ACA provision requiring insurance companies to pay goes before appeals.

Federal agents and the state fire marshal have effectively barred a federal safety panel from the site of a Texas fertilizer plant blast that killed 15 people and injured about 200 others, hampering its investigation, the panel's chairman said.

In a May 17 letter to Sen. Barbara Boxer, U.S. Chemical Safety Board Chairman Rafael Moure-Eraso asked the California Democrat to help the board obtain evidence under control of the Bureau of Alcohol, Tobacco, Firearms and Explosives that he contends is essential to the board's investigation, the Waco Tribune-Herald and Austin American-Statesman reported.

"To date, the CSB has experienced significant obstacles that potentially compromise and delay our ability to complete the `comprehensive investigation' that you have rightly demanded, and that we would very much like to produce," he wrote to Boxer. The chairwoman of the Senate Committee on Environment and Public Works has said she planned to hold hearings into the April 17 West Fertilizer explosion.

A criminal investigation "comes with certain sensitivities. You need to keep it to law enforcement only," Robert Champion, ATF special agent in charge of the investigation told the American-Statesman. He also said the decision to bar the CSB from the site was made by the State Fire Marshal's Office.

Fire Marshal's Office spokeswoman Rachel Moreno said the CSB was kept out because criminal investigators were executing search warrants.

"We have to protect evidence," she told the American-Statesman. "We need to have one report, one set of interviews; it all has to be clear cut."

Messages left by The Associated Press with ATF and the State Fire Marshal's Office were not returned Tuesday night. However, a Boxer spokeswoman said the senator had asked the agencies to respond as quickly as possible to her concerns regarding the issues raised in the letter.

In an April 30 statement, Boxer said she "cannot rest until we get to the bottom of what caused the disaster" in West and that she wants to make sure such facilities are complying with chemical safety laws.

In his letter, Moure-Eraso said the board sent 18 investigators and other experts to West within 24 hours of the blast. At the same time, ATF "assumed essential exclusive control of the incident site" with the State Fire Marshal's Office, he wrote.

"These criminal investigators have exercised exclusive control of the site for a full one-month period ... and have altered or removed almost all relevant physical evidence at the site," he wrote.

ATF and the State Fire Marshal's Office "consistently expressed the position that CSB was not permitted to conduct separate interviews, prepare expert analysis or author its own independent report," he wrote. ATF and the state fire marshal "state that because in their view this was exclusively a criminal investigation, there could be only one version of what occurred and one report."

On May 16, representatives of the State Fire Marshal's Office announced that the joint criminal investigation left the cause of a fire precipitating the blast as "undetermined."

Investigators narrowed the number of possible causes to three: a problem with one of the plant's electrical systems, a battery-powered golf cart and a criminal act. However, they could not say with certainty what caused the fire that ignited stored ammonium nitrate, said Kelly Kistner, the assistant state fire marshal.

First, the jet stream caused a cold snap by bringing Arctic air farther south than normal, but when it shifted north, it allowed tornado-causing moist air to move into the Midwest    

Other countries have long been annoyed by Irish tax laws, but the benefit to the struggling country’s economy means the rules are unlikely to change. The NYT reports.

In states like Oklahoma and Missouri, tornadoes are a seasonal threat, but government regulation and the expense of shelters rankle.    

Leaders of the Tea Party movement hope outrage over the I.R.S. inquiry will rekindle grass-roots activism that in many places went dormant after Republican electoral defeats in 2012.    

Carney's latest dust-up with the media exposes long-simmering tensions.

The actor who played Lt. Dan in "Forrest Gump" honors veterans during a trip to the Beltway.

In an address on Thursday, President Obama will attempt to lay out his justification for drone strikes, which have been in decline since 2010, and what they have achieved.    

State media says Choe Ryong Hae will head to Beijing.

North America's largest chocolate manufacturer Hershey's is veering away from tradition to bite into the world's fastest growing candy market.

According to this expert the rally in gold over several years was based on a misunderstanding.

Kaitlyn Hunt is being prosecuted for sex crimes because of encounters with a 14-year-old girl who was her high school basketball teammate.    

Parents say the Chicago Board of Education’s plan to shut 53 elementary schools is uprooting the personal and academic lifelines of the city’s neediest communities.