A former aide to Chile's ex-military leader General Augusto Pinochet has been arrested on suspicion of involvement in the killings of 13 political prisoners in the 1970s.
Col Cristian Labbe was detained with nine others on orders of a judge examining the 1973-1974 deaths.
The victims died at a concentration camp in San Antonio on Chile's coast.
Col Labbe, who later became mayor of Providencia district in Chile's capital of Santiago, has denied any wrongdoing.
A minister under Gen Pinochet, he visited the former president several times while he was under house arrest in the UK between 1998 and 2000.
During Chile's military dictatorship from 1973-1990, the retired colonel served as Gen Pinochet's bodyguard before being appointed to his cabinet in 1990.
When democracy returned to Chile, he served as mayor of Providencia for 16 years but was ousted in a bitter election two years ago.
Col Labbe was responsible for organising demonstrations outside the British and Spanish embassies in Santiago to protest against Gen Pinochet's exile.
The nine other arrestees were also former military officers. Some are already in jail for other crimes.
Around 3,200 people were killed and 38,000 others tortured during Gen Pinochet's rule, according to the Chilean government.