Britt Lapthorne has been remembered by family and friends as a character who made people laugh but was focused on achieving her goals.

Her brother Darren thanked the hundreds of people who farewelled her at a memorial service on Wednesday.

The vivacious 21-year-old student went missing in the Croatian coastal town of Dubrovnik on September 18 and her badly decomposed body was found in the sea on October 8.

“Britt was a real character, who could make us laugh, but there were times when there was a lot of fighting but she was definitely the boss of the household,” Darren told the 300 mourners at the service in memory of the backpacker at Upper Plenty Convention Centre in Melbourne’s north.

Darren also thanked the many people who supported the family and helped him and his father Dale as they searched for Britt in Croatia in their effort to bring her home.

“Without the support of people in Melbourne and Australia and people in Croatia we could not have accomplished our task,” Darren said.

He said Britt was goal-focused and knew what she wanted and she she aimed for it.

Britt’s Aunty Barbara Gibbons told the service she had called her niece “my cherub” while recounting stories of her childhood as a big screen displayed a montage of photographs.

Following the hour-long service, 21 mauve balloons were released.

As well as family and friends, the service was attended by local federal MP Fran Bailey, former federal attorney-general Philip Ruddock and Family First senator Stephen Fielding.

Croatian police were unable to determine how the university student died, and the Victorian coroner will now undertake a second inquest into her death at the request of her family.

Her body was brought back to Australia by Dale and Darren on Sunday night.

After the balloons drifted into the blue sky in the rural setting at Upper Plenty, Britt’s parents Dale and Elke and Darren walked back toward the mourners and thanked them individually.

Mrs Lapthorne cried and hugged mourners, many of whom she had never met before.

Mr Lapthorne said he wanted to establish a foundation in his daughter’s name to assist missing Australians overseas.

“We’re hoping to set up a legacy – the Britt Lapthorne Foundation – to help missing Australians overseas in times of need when families don’t have the financial backing,” he said after the service.

“It’s a great legacy, I won’t be associated with failure or have my daughter associated with failure.

Mr Lapthorne has been highly critical of the Croatian police and the Australian Federal Police’s (AFP) involvement in the investigation into Britt’s death and has called for a commitment from the federal government that her death will be fully investigated.

Mr Lapthorne said he knew Britt was murdered and he wanted answers.

“I want a commitment from the Australian government that we’re to pursue this case to the end,” he told Fairfax Radio this morning before the service.

“I’ve had various commitments but I’m not totally convinced that the commitment or the desire for the commitment is there, especially as there are other issues that seem to always come in, and that seems to be the Australian-Croatian relations and that we don’t have any rights within the jurisdiction of Croatia.”

Mr Lapthorne said he was disappointed with the poor answers provided by AFP Commissioner Mick Keelty to a Senate committee on Tuesday.

He said that before he left Australia for Croatia the AFP told him and Elke to “tone down and restrain” their contact with the media.

“(We were told) we must think of the bigger issues of Croatian-Australian relations,” he said.

“I just got furious, we screamed at them on the phone, we said, ‘you are public servants of Australia, we are Australian citizens and we are not going to allow you to sacrifice my daughter’s life for the sake of relations’.”

Mr Lapthorne said he was told last night that the Australian Ambassador to Croatia had returned to Dubrovnik and would remain there for “some period”.

“It certainly shows the Australian people’s desire to have an answer and the importance of the issue to the Australian people,” he said.