Former Nazi and cult leader Paul Schaefer has been questioned by a judge in Chile over the disappearance of a left-wing activist in 1974.
Schaefer was described as the closed community's supreme ruler
The judge ordered that he be jailed until later this week, when a decision will be taken on whether to bring formal charges against him.
Another judge is set to question him later in the week over the alleged sexual abuse of 26 children.
Mr Schaefer, 83, was deported on Sunday from Argentina.
He entered the closed court on Monday in a wheelchair under police escort, and a crowd shouted insults at him as he was taken away from the interview room under high security.
The German citizen was questioned for three hours over the disappearance of leftist Alvaro Vallejos in 1974.
There are allegations of close links between Mr Schaefer and former leaders of the military government of Gen Augusto Pinochet.
He was taken to hospital on Friday complaining of high blood pressure, and is due to undergo medical examinations this week to ensure he is well enough for the case to go forward.
Chile's most wanted fugitive, Mr Schaefer was a corporal in the German army during World War II before running a religious commune in Chile.
Colonia Dignidad, established in 1961, was cut off from the outside world and was alleged to have been a centre for torture and child abuse.
Colonia Dignidad was shut off from the outside world
In 1997, there was a police raid on the commune, but Mr Schaefer could not be found. It now appears he escaped across the border and set up a new life in Argentina. He was discovered last week near Buenos Aires with five of his closest followers, including two of his adopted children.
He faces charges in Chile of sexually abusing 26 minors.
He is also wanted for questioning in Germany on suspicion of the abuse and corruption of minors, and is under investigation in France.
In addition, he is wanted for questioning about the disappearance in 1985 of Boris Weisfeiler, an American-Jewish mathematics professor of Russian origin.