It’s a place of millionaires’ mansions, where Sunday mornings are spent quietly relaxing or paddling on the gentle waters.

It’s not a place where bodies are found.

And yet last Sunday morning, at the end of a picturesque cul-de-sac leading to the river, the partly submerged body of Cecilia Haddad was found by kayakers.

The seemingly perfect life of the beautiful 38-year-old businesswoman had been inexplicably and mysteriously snuffed out.

As police taped off the area and covered her with a blanket, shocked passers-by speculated the diminutive form must be that of a child.

Carolina Camara remembers that the last time she spoke to her friend “Cissa”, she was on top of the world.

Sporty, vivacious, curious and intelligent, the young Brazilian entrepreneur had mixed strong family ties and a spirit of adventure.

“She was in a wonderful mood,” Camara said.

It was 10.30pm on Friday and Haddad was getting ready to leave the backyard barbecue she was enjoying with friends in the Sydney suburb of Ryde to return to her nearby apartment.

The two Brazilian women had been “like sisters” since meeting 11 years ago in Perth, when their husbands took part in a trainee course for mining giant BHP. Haddad and her husband Felipe Torres had both been working in Port Hedland, gateway to the resource-rich Pilbarra.

Camara said even after Haddad moved to Sydney two years ago, there was not a day went by the two women did not speak.

Until Saturday.

When she heard nothing back from Cissa all day, a worried Camara contacted NSW Police on Sunday.

Police had already received a “concern for welfare” report about Haddad on Saturday evening from some of her Sydney friends, who found all their calls to her going through to voicemail.

The friends also tried to call Haddad’s ex-boyfriend, Mario Marcelo Santoro. He wasn’t picking up either. By then, Haddad was dead and father-of-two Santoro was on his way to Rio de Janeiro.

Friends have told homicide detectives Haddad was well-liked and had lots of mates. But police have also been told she was a “complex person” who “had a lot of things going on in her life”.

She lived alone but often had people stay over. Some friends say she used online dating sites; others say she would never go near them.

As they trace her last moments, detectives are investigating whether the popular mining executive who worked with disabled people had any secrets. In the competitive world of mining, Cissa Haddad was a rising star.

Fluent in English, Portuguese and Spanish, she moved to Australia in 2007 having studied logistics and industrial engineering at the Pontifícia Universidade Católica in her home city of Rio de Janeiro.

Marcelo Santaro also studied at the top university.

From May 2007, Haddad made her home in Port Hedland with BHP. It is a town for young people, a million miles from anywhere, where people make their own fun. It appears she met her second husband, Felipe, there. He had been working as an area project manager for three months, according to his LinkedIn page.

They married in 2008.

On her Facebook page, Haddad said she had been married earlier, in 2004.

She quickly moved up the ranks in BHP from being a contracts officer to superintendent of logistics at Port Hedland before moving to Perth in 2011 and into a senior planning role with the company.

Carolina Camara told The Saturday Telegraph her friend loved Australia.

It is not known when she split up with Torres but Haddad moved to Sydney about two years ago, where she immersed herself in the city’s growing Brazilian community.

But home in Rio was never far from her mind.

In 2016 she posted a photograph of herself and her mum Milu Muller on Facebook, next to which her mum wrote: “I love you too, we’re always happy together. I think you’re the best daughter in the world.”

Her mum was in touch with Santoro, who saw his two daughters as much as he could. “Beautiful family,” Muller posted on his Facebook page under a photograph of Santoro with the girls.

For just over a year in Sydney, Haddad worked as head of operational planning with rail freight operator Pacific National before breaking away to set up her own company, CHC Consulting, in July 2017.

According to her website, the company helped “companies of all sizes respond to industry transitions in order to stay competitive”.

A few months later, she set up a company with Santoro, D.Care, registering it at her unit in St Annes Street, Ryde.

From around the same time, the couple both worked as community support workers at disability service provider Hireup. It is not known when she split up with Santoro, who had told friends he was due to fly home to Rio some time early last week.

The last time anyone heard from Cissa was in a flurry of phone calls and texts between 8am and 9.30am on Saturday morning, during which she was “anxious about something”, detectives have been told.

When her body was found floating at Woolwich at 10.15am on Sunday, police initially treated it as a suicide or a tragic accident.

They now believe it may have been dumped near the Gladesville Bridge, 4km from where it was found. There was no identification with the body, dressed in a navy-green long-sleeve jumper, khaki cargo pants and silver bracelets on both wrists.

But as soon as police identified the body as that of Haddad and started talking to her friends their position changed rapidly.

The Homicide Squad’s Detective Acting Inspector Ritchie Sim said two clues pointed to foul play. It was completely out of character for her not to keep appointments with friends on the Saturday. And her car was found at West Ryde train station.

Detectives believe the red 2013 Fiat 500 with its distinctive black roof could be a key to her murder. A neighbour reported seeing it parked outside the St Annes Street address on the Saturday afternoon. So how did it get to the car park where it was found at 2pm on Sunday? Who drove it there? How did they leave the area? Why was it left there?

Police have been trawling through CCTV footage.

They went through the Australian Federal Police to search passenger lists on flights out of Sydney bound for Brazil — where they found Santoro’s name on a flight late on Saturday.

Detectives searched his Sydney address, trying to pin down his last movements, but stressed he is just one person of interest. It is known there were no reports made to police by Haddad about her ex lover.

But Santoro is yet to come forward and Cecilia’s family and friends are left to anguish over how such a bright star ended up in a watery grave.