Today we breathe a sigh of relief.

Aussie defense lawyer Melinda Taylor and other ICC staff are on their way to the Hague after being released from detention in Zintan, Libya.

Three weeks ago Melinda was in Libya with the permission of Libyan authorities to visit Saif al Islam Gaddafi as his defense lawyer. She was arrested after her meeting with Saif and accused of passing documents that undermined Libyan national security. She had been held in a jail cell in Zintan ever since.

Melinda's freedom comes after sustained diplomacy between Bob Carr and Abdurrahim el-Keib, the Libyan Prime Minister, and pressure from the UN Security Council, the International Criminal Court and Amnesty supporters around the world.

As Amnesty supporters, we should be proud to have contributed to the pressure that helped secure their release.

While it is great news that we have seen the release of Melinda and other ICC staff, they should never have been detained in the first place.

International Criminal Court staff enjoy diplomatic immunity under Article 48 of the Rome Statute, the international treaty that establishes the International Criminal Court.

"While it is great news that we have seen the release of Melinda and other ICC staff, they should never have been detained in the first place. "

ICC officials enjoy this immunity to the extent it is necessary for them to carry out their roles. Melinda's arrest and subsequent detention is an example of how a government may attempt to frustrate the role of the ICC if the immunity is not enforced.

Arguments have been made that as Libya is not a party to it, the Rome Statute is irrelevant and the immunity should not apply. However, when the UN Security Council referred the situation in Libya to the ICC in 2011, it established the jurisdiction of the ICC and therefore the application of the immunity in the Rome Statute.

We must also remember that there are still thousands of Libyans arbitrarily detained by militia groups throughout Libya. They must be charged or released immediately if the new Libya is going to break with the abuses of the past and genuinely implement the rule of law.

Amnesty will be launching a report on Libya's militias (like the group that detained Melinda) on 5 July. We will continue to push the Libyan authorities to seize the opportunity to break with abuses of the past and implement the rule of law.