AFTER 18 years of mystery and speculation, a coroner will deliver findings this week on the disappearance of a young soldier.

Sean Sargent was 24 when he vanished in 1999 after a house party.

Mr Sargent went to Pioneer State High School in Mackay and his father Tom retired to Bucasia.

Military police reported Sean Sargent missing three days after he went to a party at his friend Benjamin Snelling's St Lucia house.

Last month, Coroner John Hutton examined issues including the adequacy of civilian police and military police investigations into the disappearance, and whether Mr Sargent was dead or alive.

The findings will be delivered at Brisbane Coroners Court on Wednesday.

Last month's inquest heard somebody tried unsuccessfully to use Mr Sargent's bank card 27 days after the soldier and his car vanished.

It was asked why police then never requested a credit union, now known as Defence Bank, to investigate that failed transaction of April 15, 1999.

The inquest also heard rumours about Mr Sargent's sexuality shaped the investigation into his disappearance.

But Mr Sargent's family, friends and a former girlfriend all said there was no evidence of the missing soldier being gay or bisexual.

At an earlier hearing in May, military investigators said they did not know if Mr Sargent had the skills to create a new identity and live in secret. - NewsRegional