Juan Rodriguez is accused of killing his two kids, aged one, after they were left for eight hours on the backseat while temperatures soared to 30C in New York.
Witnesses reportedly heard him scream “I killed my babies” after returning to his Honda Accord in the Bronx.
The New York Post said that the babies called Luna and Phoenix died with an internal temperature in the car of 42C.
He told cops at the scene: “I assumed I dropped them off at the day care before I went to work.
“I blanked out. My babies are dead! I killed my babies”
“I blanked out. My babies are dead! I killed my babies!”
The disabled war veteran was in tears after he left court with his wife, Marissa, having been given bail.
Family friend Temple Barros, 41, who lives with the family said that Rodriguez regularly took the twins to day care in the morning.
He said: “(He’s) an amazing guy. He’s always been there for his kids. Always.
“This is just a horrible situation. The family isn’t doing so well.”
Rodriguez, 39, is alleged to have parked up at around 8am before work.
He returned to the car at 4pm after finishing his shift at the Veterans Association hospital and found the two babies foaming at the mouth.
A member of the public is then believed to have called the emergency services.
Rodriguez has been charged with two counts of manslaughter and criminally negligent homicide.
The family had just celebrated the twins’ first birthday with a big party a neighbour reportedly said.
Rodriguez has two older children from a previous marriage who also live at home.
Devastated neighbours have made a memorial out of candles on the street.
The neighbour continued: “It’s shocking. I know there are two little angels in heaven tonight.
“I hope they get a beautiful burial.”