SOFIA, Bulgaria (AP) – Bulgarian judicial authorities on Friday started questioning a group of medics who said they were tortured in Libya while in prison on charges of infecting children with HIV.

The Criminal Investigation Service said in a news release the five Bulgarian nurses and a Palestinian doctor had started to testify, but did not release further details.

All six medics were freed last month. Libyan leader Moammar Gadhafi’s son, Seif al-Islam Gadhafi, on Wednesday admitted the six were tortured with electric shocks, but made no apology and said some torture claims were “lies.”

Bulgaria’s prosecution service this year charged several Libyan officers with torturing the medics to extract their initial confessions, and has said it is intent on pursuing the case.

A Libyan court in 2005 rejected torture lawsuits by the medics against 10 Libyan officers.

The nurses and the doctor were arrested in 1999 on charges of deliberately infecting more than 400 Libyan children in a Benghazi hospital with HIV. They were twice sentenced to death despite testimony from AIDS experts that the children, 50 of whom died, were infected by unhygienic conditions at the hospital. They were released into Bulgarian custody after Libya and the EU struck a deal for millions of dollars in aid to Libya, and soon afterward a major deal was announced between European arms makers and Tripoli. Once back in Bulgaria, the medics were pardoned and freed.