Shackleton died on the weekend at the age of 91 after a long illness, having campaigned for decades for justice for the Australian-based journalists slain by Indonesian special forces in 1975 and for self-determination for Timor-Leste.

Horta, on Facebook, said “Thank you for ever. For ever we will remember you and the Balibo Five and Roger East. Your soul rests with us in Mt. Ramelau.”

The President noted that Shirley's husband Greg Shackleton, news reporter for Australia's Channel 7, “was cold-blooded murdered” in Balibo on 16th October 1975 along with four other newsmen. A sixth newsman Roger East was captured and murdered on 7th December 1975.

“Shirley spent the rest of her life campaigning for Timor-Leste's freedom and for the truth about the circumstances of the murder of the five journalists...2 Australians, 2 British and one New Zealander,” Horta said.

Shackleton once said:  “While I continued to accept every opportunity to demand a full judicial investigation into the murders that took place in Balibo, on October 16th, 1975, I was forced to change direction after December 7th 1975. Indonesia invaded East Timor and the TNI (Indonesian military) began to inflict a policy of genocide on the civilian population. One could hardly put the killings of five white men ahead of an entire nation. Besides I knew the three Channel 7 men very well and I knew they would approve.”

A memorial service for Shackleton will take place Thursday at Motael Church, Dili.