"She was supposedly Heidi's friend for a long time", a family member of Broussard's said in an interview to PEOPLE. The woman's fiancé, Shane Carey, reported her missing.
Tammy Broussard said the body was found in a auto trunk.
Early signs indicate it is Margot however DNA tests are underway to confirm her identity.
Broussard and her newborn daughter were last seen around 7:30 a.m. on December 12, dropping Broussard's son off at an elementary school, police previously said. Police said they believe she returned to her residence, and her boyfriend later reported her missing when she and his daughter did not return before the 6-year-old needed to be picked up from school activities.
A baby girl was also found alive and healthy at the home, the statement said.
The vehicle in which the body was found is registered to a close friend of Broussard's, police sources told ABC affiliate KEYE, and at least one person has been taken into custody by police. The baby has been placed in Child Protective Services custody, and the body is now with a medical examiner, the local news outlet reports. Investigators went to the home Thursday, one week after Broussard and the baby, Margot Carey, were reported missing.
United States reaches 'deal in principle' with China on trade
He added: "It may be that the Chinese made a purchase offer, including energy, and Trump said yes to the tariff cut". President Trump has previously mentioned, however, that China would purchase up to $50 billion in agricultural goods.
One person has been arrested and charged with two counts of kidnapping and one count of tampering with a corpse, Herries said. "We've been knowing her for a long time".
Police say more charges are possible.
Fieramusca was being held at the Harris County Jail on $600,000 bond.
Earlier this week, investigators said they had no reason to believe that the two were harmed in any way but on Thursday night, several law enforcement agencies, including the Federal Bureau of Investigation, responded to a Houston-area home where a body, believed to be Broussard's, was found inside the trunk of a auto, KTRK reported, citing online records and a source.
During the search, police found a baby whose "visual appearance is consistent with that of baby Margot", Herries said.
Hanley said during the press conference additional charges were likely as evidence was uncovered, and that detectives were still working multiple scenes between Austin and Houston.
Broussard's fiance, Shane Carey, told ABC's Austin affiliate, KVUE, that her auto and all of her and the baby's belongings were still at their home, and there were no signs of a struggle.