Chadian officials freed three Spaniards of the flight crew and a Belgian pilot charged with participation in an alleged conspiracy by a French charity to transport over 100 African children to Europe.
One of the three Spaniards smiled and flashed a thumbs-up signal as he left the courthouse in the Chadian capital, N'Djamena. The group was expected to be flown back to Europe later Friday.
Chadian lawyer Jean-Bernard Padare, representing the liberated Europeans, said the four had been charged with complicity in the alleged kidnapping plot but were ordered released by a judge.
Six workers with the French charity Zoe's Ark workers remain in custody in Chad. They are charged with the attempted kidnapping of 103 children. A conviction could mean 20 years in prison at hard labor.
Spain hailed the release of its citizens.
"I want to take the opportunity to express from here our sincerest gratitude to the government of Chad and the judicial authorities for this decision," Deputy Prime Minister Maria Teresa Fernandez de la Vega said.
In total, 17 Europeans were arrested after Zoe's Ark was stopped on Oct. 25 from flying the children to Europe. The group said the children were from Sudan's Darfur region and that it intended to place them with host families. Zoe's Ark maintains its intentions were humanitarian and that it had conducted investigations over several weeks to determine that the children were orphans.
However, France's Foreign Ministry and others have cast doubt on the claim that the children were orphans from Sudan's western Darfur region, where fighting has 2003 has forced thousands to flee to Chad. Aid workers who interviewed the children said a majority of them reported living with at least one adult they considered a parent.
French investigators are also looking into the activities of the aid group. In Paris on Friday, investigating judges searched the office of the Capa media agency. Capa reporter Marc Garmirian was among the journalists detained in the case and released Sunday. He filmed the group for weeks leading up to their arrest. The judges are looking into possible charges of illegal adoption and fraud against the aid group.
Three French journalists and three female Spanish flight crew members were released Sunday, and flown from the country by French President Nicolas Sarkozy. The Spaniards were contracted by Zoe's Ark to fly the African children to France. The Belgian, also hired by the French charity, had piloted a plane carrying some of the children around Chad.
The episode comes at a sensitive time in Chad's relations with Europe. The European Union is planning to deploy a peacekeeping force in Chad and Central African Republic composed largely of French soldiers. The 3,000-strong force is intended to help refugees along the two nations' borders with Darfur.
In July, Sarkozy's then-wife, Cecilia, helped broker the release of five Bulgarian nurses and a Palestinian doctor held for more than eight years in Libya, where they were accused of deliberately infecting hundreds of children with the AIDS virus.