Missing mother's body found in car but newborn baby 'safe', say police as kidnapping suspect charged

Heidi Broussard and three-week-old daughter disappeared last week

The body of Heidi Broussard was discovered in Houston a week after she was reported missing from her Austin home. Her newborn baby was found alive and safe. (Austin Police Department)

The body of a mother who went missing with her newborn baby last week has been found in the boot of a car in Texas, police have said.

Heidi Broussard's three-week old daughter has also been located and is "safe and healthy," detectives said on Friday.

A suspect arrested on Thursday has been charged with tampering with a corpse and two counts of kidnapping.

Detective Brad Herries told reporters on Friday that "early indications lead us to believe" the body found in a car outside a Houston house on Thursday was Ms Broussard, 33, of Austin.

Her baby daughter, Margot Carey, has been placed in the care of Child Protective Services.

The suspect remains in custody with a bond set of $600,000.

Police have not confirmed the name of the suspect, but Harris County Sheriff's Office records show that Magan Rose Fieramusca was booked on the same charges with the same bond on Friday.

Records show the car in which Ms Houssard's body was found is also registered with Ms Fieramusca.

Media reports suggest Ms Fieramusca was Ms Broussard's "close friend" and pretended to be pregnant while she carried Margot.

FBI special agent Christopher Combs said Ms Broussard's Austin community has endured a devastating week. He added they had been "praying to find Heidi alive" but "we don't think that is the case".

Mr Combs said Margot was in "very good health."

Ms Broussard and her newborn were last seen at 7.30am on 12 December as she dropped her six-year-old son off at school.

Police say she likely returned home before she disappeared.

Shane Carey, Ms Broussard's husband, said he last spoke with her at 8am.

Ms Broussard and the couple's daughter, then two weeks old, were nowhere to be found when Mr Carey returned home that afternoon.

She was reported missing that night.