(NBC) – The investigation into the disappearance of a Texas mother and her newborn baby has gotten more intense.
The FBI has now joined the search, and the parents of Heidi Broussard are speaking out.
FBI teams have been going door to door at her apartment complex in suburban Austin.
“I see kids like this on the news you’re NEVER thinking it’s going to be yours,” said David Broussard, Heidi’s father.
“Whoever it is knows anything just please come forward,” her mother, Tammy Broussard said.
It’s been six days since their daughter and 3-week-old granddaughter Margot vanished without a trace.
Heidi’s car is still parked at a parking lot near her apartment with a baby car seat inside.
“Something happened. She would not just leave,” Tammy Broussard said.
Broussard also has a 6-year-old son who she dropped off at school shortly before disappearing.
“Our assumption is that they’re alive and the sooner that we can find them, the better,” said Detective Brad Herries with the FBI.
Investigators have ramped up search efforts, but say they have no “person of interest.”
They’re also not sure if the disappearance is “nefarious” or if the mother left on her own accord.
“She wouldn’t leave…not without an ID, all of her cash was in her purse, her whole purse was here,” said her boyfriend, Shane Carey.
There is an independent search group with people and technology that is waiting for the FBI to give them the green light. A church group is also going out this weekend to continue their own search.
Broussard is 33 years old, 5 foot 3 inches and 150 pounds with long, dark hair with highlights.
Anyone with information on the whereabouts of Heidi Broussard or Margot Carey should call the Austin Police Department.