A baby, who was believed to be inside the car when a woman tried to ram it through the security barricades at the White House, was reportedly aged between 12 and 18 months, NBC News in Washington said.
More top news
Three people who had been arrested on suspicion of murder have been released without any further action.
Zimbabwe's ruling party is to hold a meeting after Robert Mugabe ignored an ultimatum to resign or face impeachment.
The former WTA World No 1 doubles and No 2 singles champion died after a long battle with cancer.