Cecilia Haddad’s death ‘cold, calculated, horrible’ says brother

The brother of Cecilia Haddad has spoken for the first time about the former mining executive’s death, labeling it a “cold, calculated and horrible” crime.

Joao Haddad spoke exclusively to 9NEWS, saying his sister "adored" living in Australia, and loved the Australian people.

Cecilia's clothed body was found in Lane Cove River in Sydney on April 29.

"It's a brutal crime, executed in a very cold, calculated and horrible way that no-one deserves, especially a sweet girl as (sic) Cecilia," Joao Haddad said.

Asked how he wanted Australia to help the investigation into her death, he said it was important to bring the evidence collected in the Australian investigation to Brazil.

The recently-arrested Mr Santoro has given no response to police, and has been jailed awaiting trial.

It's alleged he strangled Cecilia to death and dumped her body in the river after she tried to break up with him.

The Haddad family has said they felt no relief at Mr Santoro's arrest, knowing the legal process is a slow one.

However, they have said they are grateful for the work done by Australian detectives so far.