New video has emerged of the man claimed to be Australia’s first suicide bomber.

The video appears to be published by the Al Qaeda-linked group, Jabhat al Nusrah, which has previously said the Australian blew himself up in an attack on a Syrian army checkpoint in north-east Syria in September.

It is the most revealing insight yet into the man’s last hours and shows the group preparing the massive truck bomb used in the attack.

The video shows the jihadist identified in a previous internet posting as Abu Asma al Australi, standing on the back tray of the truck used in the suicide bombing. However, because the face in the video is obscured it is impossible to be sure who it shows, but the bomber is suspected of being a Brisbane man named Ahmed.

In the video, the bomber dedicates his actions with a verse from the Quran: “To all those who believe it is your destiny to be buried in the way of God and you accept for life on earth, the afterlife, because the joys of life on earth in the afterlife are few. So trust and worship God.”

Since sketchy images of the bombing and a still image of Abu Asma emerged identifying him as an Australian in September, Australia’s intelligence and police agencies have been trying to trace his route from suburban obscurity to jihad.

It is understood they have identified the man they believe carried out the bombing.

However, his family has denied he was involved and insists he is still alive in Turkey.

Because of the difficulty gathering evidence in Syria the ABC cannot name him fully for legal reasons.

It is understood he travelled to the Middle East in the middle of this year but then sent his young family home. A senior counter terrorism official has told the ABC that, by that time it seemed clear he had no intention of following them.

In the video, standing atop the explosives laden truck Abu Asma says: “This is a duty imposed on us and the best of people are those who fight for the sake of God. So if you are afraid, why are you afraid? For your wives and your children? Trust in God. In the West or in any country, you think you are men? Or (that) you are living a good life? Today real men are living in the land of Jihad. They are our brothers, they are the Muslims who defend the religion of God.”

Number of Australians fighting in Syria rises

The case offers an insight into a troubling phenomenon.

There are signs that others who have expressed an interest in heading to front lines have been able to use contacts in Australia with armed groups in Syria. And there is evidence they have raised money in Australia before leaving, because the militias are happy to get new recruits but want them to bring money for weapons and supplies.

The Australian Federal Police (AFP) says over the past 12 months there has been a substantial increase in the number of Australians going to join hard-line groups, including Jabhat al Nusra.

In just a year the number has risen from a few to 20 or 30, possibly more.

That is about the same number as those going from other western countries with much larger Muslim populations and it is not clear why there is such an outsized interest from Australia.

In the video, Abu Asma stands in front of the truck. Large apparently metal panels are fitted to its front in an effort to protect the driver from gunfire. He bids farewell to fellow jihadists then urges more foreigners to come and join the fight.  “This is a message to all my brothers in the world: Today Jihad is a duty of every Muslim, to carry a weapon and come to the land of Jihad. The land of al Sham is a blessed land. Today Jihad is duty imposed on every Muslim, so rise up Muslims.”

AFP working with Turkey, Lebanon

To stop Australians from heeding the call of battle, the government has been cancelling their passports. The most recent annual report from the domestic spy agency, ASIO, says it issued 18 adverse security assessments – to deny a passport or cancel one – in the last financial year. ASIO will not detail the reasons but it is believed most of them related to Syria – and the trend continues this financial year.

Obviously, dozens have slipped the net, but the effort to trace them does not end in Australia.

Turkey is the most important gateway for foreign fighters headed into Syria.

And the ABC can reveal that Turkish authorities are cooperating in the effort to keep track of the Australians. They are doing much more than simply reporting on who arrives in Istanbul. They have actively cooperated in investigations: providing information on the activity of Australians flagged by the AFP.

Lebanon has also been an important gateway for Australians travelling to Syria and the AFP also cooperates with the Lebanese authorities.

The fears about what these men might do in Australia when they head home are well publicised. A senior counter terrorism official has told the ABC none of those suspected of taking up arms has returned.

That day of reckoning is yet to come.