The indictment charged that the group including Nijmeijer, who is believed to have joined the Revolutionary Armed Forces of Colombia (FARC) in 2002 when she moved there, detained three Americans in brutal conditions in the jungle, at times transporting them across the border into Venezuela to avoid capture.
A federal grand jury slapped them yesterday with seven counts including hostage-taking, conspiracy to provide support to terrorists, and weapons charges stemming from their capture in 2003 of Americans Marc Gonsalves, Keith Stansell and Thomas Howes when their reconnaissance plane crash-landed in the Colombian jungle.
The plane's American pilot and a Colombian national onboard were immediately executed by the FARC, and four of the Colombian defendants face the extra charge of pre-meditated murder in the death of the US national, the statement said.
The Americans were among several hostages including French-Colombian Ingrid Betancourt, a former Colombian presidential candidate, rescued in a daring raid by Colombian military forces in July, 2008.
"We will not tire in our pursuit of all those responsible for this crime," Assistant Attorney General David Kris said in a statement announcing the indictment.
US Attorney Ronald Machen said the indictment "demonstrates our firm resolve to bring to justice every last FARC commander who played any part in this brutal act of terrorism."
If caught and convicted, each defendant would face up to 60 years in prison, the maximum allowed under Colombian law for nationals extradited to the United States. The four charged with murder face an additional 60 years behind bars, the Justice Department said.
Nijmeijer, a 32-year-old former schoolteacher who goes by the code-name "Alexandra," is believed to have served as personal assistant to Jorge Briceno, a top FARC commander who was killed in a September government raid on his hideout.
According to Colombian authorities, Nijmeijer is the only European fighting with the FARC, Latin America's longest-running insurgency. "The FARC has authorised the use of violence and attacks against American citizens to forward their mission of terrorism," FBI special agent in charge John Gillies said.