The family of Cecilia Haddad, the Brazilian woman found dead in a Sydney river, have spoken out on the suspected murder of the 38-year-old businesswoman.
As police ramp up their search for a man Haddad was "involved" with, Ms Haddad's devastated brother described his sister as vibrant and successful.
“I am devastated because I love my sister very much and I am totally shaken by her death and the way it happened,” João Müller Haddad, an artist still living in Rio de Janeiro, told the .
“It is very difficult for me to talk about her, it is still very recent.”
Her Brazilian mother, Milu Muller, is too sick to fly to Australia after recent surgery.
"I do not know if I will survive this tragedy," Ms Muller said in a statement to Fairfax Media on Thursday.
"Maybe if they arrest the murderer, I may have some relief. Thank you and please do everything to help catch the monster that did this."
Kayakers found the Brazilian national's fully-clothed body floating in the Lane Cove River at Woolwich on Sunday morning, some six kilometres from her Ryde home in Sydney's northwest.
NSW Police are now working to piece together the mining executive's final 24 hours, and have named a man wanted for questioning in her death.
Cecilia Haddad was a Brazilian businesswoman. Source: LinkedIn
According to AAP, the man believed to have flown to Brazil around the time Ms Haddad was found dead has been named as Mario Marcelo Santoro.
Investigators first confirmed on Wednesday evening they were trying to reach a man known to Ms Haddad who flew home to Brazil over the weekend.
AAP understands Ms Haddad and Mr Santoro were "involved". He is a person of interest in the case.
Mr Santoro and Ms Haddad both worked as community support workers at disability service provider Hireup after mid-2017, their LinkedIn profiles reveal.
They attended the same university in Brazil, according to their online resumes.
Mr Santoro is listed as a managing director of D.Care, which is a registered partnership between "C Haddad & M Santoro" in government databases.
D.Care's address is listed as Ms Haddad's residential address in Ryde.
Flowers are seen near the Lane Cove River where the body of Brazilian woman Cecilia Haddad was found. Source: AAP
As yet there are no suspects in the case, but Mr Santoro, as well as other Sydney-based friends and associates, are persons of interest.
AAP understands investigators are still trying to determine the movements of Ms Haddad's Sydney friends and associates around the time of her death.
Investigators on Thursday travelled to Perth to interview other friends and former colleagues. Ms Haddad arrived in Western Australian in mid-2007 and worked with BHP Billiton.
Police initially said Ms Haddad made her last known phone calls to friends between 8am and 9.30am on Saturday.
But detectives now believe she spoke with other people in the 24 hours before her body was found on Sunday. They've yet to come forward.
Forensic pathologists have completed a post-mortem on Ms Haddad's body.
Detectives have said the popular 38-year-old's distinctive Italian car - a red Fiat - could be key to unravelling her mysterious final hours.
The sedan was found parked at West Ryde train station on Sunday afternoon.
Ms Haddad's ex-husband, Felipe Torres, who detectives believe was in Perth at the time of her death, flew from Western Australia to formally identify her body.
