Detectives found suspected blood stains in the car of slain mother Gladys Machado, who was murdered last month along with her two young daughters, according to court documents.

The discovery, newly detailed in search warrants filed in Miami-Dade Circuit Court, corroborates the confession of her estranged husband, Alberto Luis Sierra, who is charged with their murders.

According to Miami-Dade police, Sierra admitted to stabbing his wife inside her car, then driving her and her children to their nearby home.

There, Sierrra suffocated each with a plastic bag, raping Machado, 29, and her 8-year-old daughter, Julia, police said. In a crime that shocked South Florida, their bodies — Machado was nude, the children clothed — were discovered last month in a bedroom closet of their Flagami-area home.

DNA samples taken from Julia matched Sierra, who police say confessed to the murders after he was confronted with the forensic evidence.

Sierra, 28, is charged with three counts of first-degree murder and two of sexual battery. He is expected to be indicted soon, and will likely face the death penalty.

The couple had recently split up. Machado, a mother of three, had been living with her grandmother in Homestead while Sierra had moved into his mother’s townhome in Kendall.

Machado was last seen the evening of Nov. 10 when she left Homestead for a shopping trip with her two daughters, ages 8 and 4. She left her 6-year-old son with her grandmother.

According to an arrest report, Sierra accompanied Machado and her daughters to the Mall of the Americas in Machado’s 2004 gold Nissan Altima. During an argument in the car, Sierra used a knife to cut Machado.

Afterward, he drove her to their home on the 7300 block of Northwest Fourth Street, which had been vacant since they split. A woman who rents an efficiency saw the Altima there that night, but it was gone by 11:30 p.m.

After the same tenant found the bodies three days later, the Altima remained missing until Nov. 19. That’s when officers discovered the car parked in a guest spot at Kendall’s Calusa Club apartments, 8810 SW 132nd St., across the street from Sierra’s mother’s home.

The Altima was backed into some bushes “so as to conceal the tag number,” the warrant said.

Blood was found on both the passenger and driver’s side seats. Detectives swabbed many parts of the car for DNA samples, and found a woman’s T-shirt “with possible semen stains,” the warrant said.

Investigators are awaiting more testing on all the items seized. Inside Sierra’s home, police detectives also found Machado’s debit card.