Investigators say a video also shows Randy Jerome Pozdol raping the children's unconscious mother, The Miami Herald reported. The woman died in 2006 of a drug overdose, and police are trying to determine if Pozdol was involved.
Pozdol, 67, had been charged with state child pornography charges in Miami and rape in Broward County. A grand jury indicted him on federal charges last week of producing and distributing child pornography.
He faces a life sentence if he is convicted. Prosecutors say a federal case will be less taxing for the victims because everything will be heard in a single court and the two children will not have to give depositions as they would for a state trial.
The children's mother, who lived in Dania Beach, died from a combination of morphine and an antidepressant. Relatives said Pozdol showed up at her home after the body was discovered.