(CNN) -- Frank James, the man authorities have said was behind the mass shooting inside a New York City subway that left dozens injured in April, now faces 10 counts of a terrorist attack and other violence against a mass transportation system, according to a superseding indictment returned by a federal grand jury Friday.
In May, James had pleaded not guilty to one count of the charge and one count of discharging a firearm during a crime of violence.
The updated total of 10 reflects the number of people wounded by gunshots, with the victims identified in the indictment by their initials. CNN has reached out to a court-appointed attorney for James for comment on the new counts.
James, 62, is accused of setting off smoke grenades and firing a handgun 33 times on a crowded N train traveling toward the 36th Street station in Brooklyn's Sunset Park neighborhood on April 12. The attack left 19 other people injured, officials said.
"The superseding indictment does not change the evidence we intend to introduce at trial, which has been produced and will be produced to the defense in discovery," a letter submitted by prosecutors with the new court document says.
If convicted, James would face up to life in prison on each of the 11 counts in the new superseding indictment, according to the US Attorney's Office for the Eastern District of New York.
James has a lengthy criminal history and had talked about violence and mass shootings in videos posted on YouTube, including one uploaded days before the shooting.
The suspect was known to New York City authorities before the attack. He has nine prior arrests in the city dating from 1992 to 1998 for offenses including possession of burglary tools, a criminal sex act and theft of service, NYPD Chief of Detectives James Essig said.
Prosecutors have said the alleged Brooklyn subway shooter's DNA was obtained through an authorized search warrant.
When arraigned in May, James was asked his educational background and said he was born in the Bronx and listed several schools he attended there.
"I have a GED," James said in court. "I have some certificates from various trade schools."