ATLANTA, Georgia (CNN) -- Four active-duty U.S. soldiers -- three of them elite Army Rangers -- have been arrested and charged with planning to rob drug traffickers.



A courtroom sketch shows David White, left, Stefan Champagne, center, and Carlos Lopez.



Wearing street clothes, Rangers Carlos Lopez, 30, and David Ray White, 28, and Army medic Stefan Andre Champagne, 28, appeared in federal court Friday.



They're charged with conspiracy to possess and distribute cocaine and with carrying firearms in connection with that conspiracy.



U.S. Magistrate Judge Alan Baverman ordered them held in custody until a preliminary hearing Wednesday.



Another Ranger, Randy Spivey, 32, is scheduled to appear in court Monday.



"It is a sad day when members of one of America's most elite corps of soldiers, the Army Rangers, are alleged to have become involved in criminal activity," U.S. Attorney David E. Nahmias said of the case.



"These men were trained to defend the people and principles of this country, not to use their skills to steal cocaine from drug dealers at gunpoint."



Lopez, White and Champagne were arrested Thursday at a storage facility in Sandy Springs, Georgia, a suburb just north of Atlanta, by agents of the Bureau of Alcohol, Tobacco, Firearms and Explosives who had set up a sting operation.



Spivey was apprehended at Camp Frank D. Merrill, an Army Ranger training center in Dahlonega, Georgia, on Friday, the ATF said. Dahlonega is about 60 miles north of Atlanta.



Lopez, White and Champagne were to commit the robbery while Spivey covered for them back at the camp, where the men are stationed, according to an affidavit filed with U.S. District Court.



All four were to get a cut of the spoils of the robbery, the affidavit from ATF Agent Brett Turner says.



The investigation began in November, when the ATF "became aware" that some soldiers were interested in robbing drug dealers of their cocaine, Turner says.



He posed as a disaffected security guard for the drug traffickers who wanted to "rip them off." The first try to set up the "robbery" failed, but a second attempt earlier this month succeeded, leading to the arrests at the storage facility and, a day later, the Ranger camp.



A subsequent search found that Lopez, White and Champagne were carrying semiautomatic pistols and had an AR-15 assault rifle and a field pouch with 15 magazines of ammunition for it in their vehicle. Agents also found a ski mask, binoculars and a Taser among the items the men brought with them.



The four soldiers face minimum mandatory sentences of 10 years in prison each for the drug conspiracy and an additional five years, consecutive, for the weapons allegation.



The Army Rangers are an elite light infantry fighting force capable of deploying anywhere in the world within 18 hours.



They became a permanent presence in the U.S. military in the 1970s. From the Colonial Era until that time, Rangers were activated for specific missions or conflicts and then deactivated when their work was completed. E-mail to a friend
what The Army Rangers are? Arrests made after ATF agents set up a sting operation what did they do when did it start who are are an elite light infantry fighting force? who said  ATF "became aware" some soldiers wanted to rob dealers of their cocaine?
elite Four active-duty U.S. soldiers planning to rob drug traffickers. 1970s. Army Rangers Agent Brett Turner
question: what The Army Rangers are?, answer: elite | question: Arrests made after ATF agents set up a sting operation, answer: Four active-duty U.S. soldiers | question: what did they do, answer: planning to rob drug traffickers. | question: when did it start, answer: 1970s. | question: who are are an elite light infantry fighting force?, answer: Army Rangers | question: who said  ATF "became aware" some soldiers wanted to rob dealers of their cocaine?, answer: Agent Brett Turner