The man accused of kidnapping and raping three women over a decade in his home is due back in court and will face further charges.
Ariel Castro, of Cleveland, Ohio, was originally accused of 329 counts covering only part of the timeframe of his alleged crimes. On Friday, a grand jury expanded the charged to a total of 977.
The 53-year-old has been in custody since his arrest on May 6, shortly after the women finally managed to escape.
Castro has been charged with two counts of aggravated murder related to one act, saying he purposely caused the unlawful termination of the pregnancy of one of the women.
The new, 576-page indictment also charges him with 512 counts of kidnapping, 446 counts of rape, seven counts of gross sexual imposition, six counts of felonious assault, three counts of child endangerment and one count of possessing criminal tools.
The three women appeared in a YouTube video last week to thank people who donated to a fund created to benefit them. Otherwise they have sought to stay out of sight and have appealed for privacy.
Castro is scheduled for trial on August 5, a date that could be delayed if the defence requests more preparation time.
He has pleaded not guilty to the earlier indictment of 329 counts. His legal team has hinted that he would plead guilty if the death penalty was ruled out.
Castro is accused of repeatedly restraining the women, sometimes chaining them to a pole in a basement, to a bedroom heater or inside a van. The charges say one of the women tried to escape and he assaulted her with a vacuum cord around her neck.
Amanda Berry, Gina Dejesus and Michelle Knight disappeared separately between 2002 and 2004, when they were 14, 16 and 20 years old. Each said they had accepted a lift from Castro, who remained friends with Ms Dejesus’s family and even attended vigils over the years marking her disappearance.
Ms Berry has a six-year-old daughter fathered by Castro, authorities said.
Castro has been held on $8m (€6m) bail. Cuyahoga County jail logs show him spending most of his time sleeping, lying on his bunk, watching TV and occasionally drawing or exercising.