(HOUSTON) — A body discovered at a home outside Houston is believed to be that of Austin mother Heidi Broussard, who went missing with her infant daughter last week, according to a person familiar with the investigation.A 1-month-old infant was found alive at the scene, authorities said.A dozen officers from the Texas Rangers, Texas Department of Public Safety, FBI and Austin Police Department converged on the house in northwest Harris County Thursday evening as part of the investigation into the week-old case, according to ABC station KTRK.Authorities were focusing on a car in the back driveway of the house, KTRK reported.Broussard, 33, and her infant daughter, Margot Carey, were last seen dropping off a child at Austin’s Cowan Elementary School on the morning of Dec. 12, according to the Austin Police Department.Investigators believe that Broussard and her child returned home to their apartment complex near West William Cannon Drive and South First Street after they left the school. They had not been heard from since, police said.Broussard’s fiance, Shane Carey, told Austin ABC affiliate KVUE that her car and all of her and the baby’s belongings were still at their home, and there were no signs of a struggle.Investigators tell ABC News that they feared foul play from the start because one of Broussard’s children was missing and one was left behind. Investigators said that if a mother were to run away voluntarily, she would likely take both children or neither.The couple has been together for nearly 10 years, Carey said.The investigation, which was initially handled by the Austin Police Department, expanded over the last week to involve the Texas Department of Public Safety, the Texas Rangers, the Texas Parks & Wildlife Department and the FBI’s Child Abduction Rapid Deployment team, with authorities setting up a command post in South Austin to coordinate efforts. Copyright © 2019, ABC Audio. All rights reserved.