Geraldine Willesee – The nightmare of East Timor followed my father to his deathbed. "Two hundred thousand dead... 200,000." A lifetime of politics poured into a single nugget of horror. "Two hundred thousand dead."

My father, Don Willesee, was the Australian foreign minister when Indonesia invaded East Timor in 1975. When the five journalists were shot dead at Balibo. And for 26 days afterwards.

In his dying days in 2003 he talked again, bitterly and unforgivingly, about Australia's role in the Indonesian invasion of East Timor. But we didn't return to the Balibo Five. We hadn't talked about the dead journalists since the time he'd confessed to a decade-long recurring nightmare in which his own journalist children suffered the same fate in an unknown war zone.

But evidence given in this year's inquest into the death of one of those journalists, Brian Peters, hit memory buttons. My father told me two things about the Balibo killings. Two government secrets. The revelations came at emotional moments, the first only months after the media workers were shot dead on Thursday, October 16, 1975.

I was alone with Dad and he suddenly started talking about Balibo.

His eyes teared up and his voice steeled. "You know, we were supposed to keep a lid on it until the next week. But I couldn't stand the thought of those poor families going through the whole weekend not knowing. So I quietly made sure that they'd be told."

I was stunned into silence, as much by my father's wet eyes as by the information. I never asked how he did it, assuming – wrongly – that a staffer or department official had been co-opted. But he'd been in Canberra a very long time and had quickly found someone able and willing to defy the cover-up decree and then stay quiet about it.

At the inquest, journalist Gerald Stone, a television news director in 1975, gave evidence that he had been told in Darwin on Saturday, October 18, by "a government agent", that the boys were dead. I had called him earlier to ask if he could shed any light on how and when the families had been told of the deaths. I told him my father's story of secretly having the families informed. That triggered his memory.

Stone and a colleague, in Darwin looking for their crews, were approached by a man who they instantly agreed was "a spook". He told them they could stop looking for their boys because they were all dead. And then he walked off. Needless to say, Stone had no intention of passing on, unverified, a story from a stranger.

Thankfully, my father never found out about this ham-fisted approach. But the cover-up of the journalists' killings meant distressed families still had days to wait before getting the truth.

The other thing my father told me was that the Indonesians had murdered the five Australians.

Context is all, and this statement came during an animated discussion about what happened at Balibo. It was still the 1970s and I was mounting an argument against the "caught in the crossfire and accidentally killed" claim, finally saying that the Indonesians had murdered them. "Of course they bloody well murdered them," he spat out angrily before walking off.

As the inquest progressed, I started digging and received almost 6kg of material from the national archives. Despite it being more than 30 years after the event, I was still denied full access to my father's ministerial files. Apparently nothing much happened in the foreign affairs portfolio for most of October 1975, except for the visit of the Indonesian ambassador to the foreign affairs minister the day before the invasion.

Notes of the meeting reveal a frosty exchange, with the ambassador assuring the foreign minister that Indonesia would not invade. The Australians already knew when they would invade. I tracked down my father's former staff and they confirmed the cover-up. One said: "Yes, your father took part in the cover-up – with a gun at his head."

Another confirmed having seen the infamous intelligence intercept telling of the deliberate killing of the journalists by the Indonesians. Another told me Dad considered resigning over Balibo.

When I told one former staffer of Dad's attempts to inform the families, he expressed surprise: "I thought he'd been talked out of that," he said.

I asked one why my father had not followed through on his instinct to resign from the cabinet: "He was a Labor man, and in the end he couldn't bring himself to damage a Labor government."

Dad decided not to stand again at the next election. Publicly he said he was leaving because of his wife's ill-health. It was a moot point, of course: the entire government would soon be out on its ear. After 26 years in parliament, he had only 26 days left.

I contacted the coroner's office and gave them the information I had gathered. Shortly afterwards Geoff Briot, my father's former chief of staff, known in those days as the principal private secretary, gave evidence to the inquest. To my knowledge, he was the only person from the foreign minister's office to be called. Legally, my account is only hearsay. The results of the inquest will be delivered on November 16.

[Geraldine Willesee, a former Canberra journalist, is the daughter of former Labor foreign minister Don Willesee.]