The owners of a nursing home where 35 patients died in the aftermath of Hurricane Katrina were indicted Wednesday on charges of negligent homicide and cruelty to the infirm.

A St. Bernard Parish grand jury took about four hours to return the indictment on 35 counts of negligent homicide and 64 counts of cruelty to the infirm against Salvador and Mabel Mangano, who were arrested about two weeks after the Aug. 29, 2005, storm. Their nursing home, St. Rita’s, is in the rural St. Bernard Parish community of Poydras.

The Manganos’ arrest represented the first major criminal prosecution arising from Katrina, which flooded 80 percent of New Orleans and virtually wiped out neighboring St. Bernard Parish. The Louisiana death toll was nearly 1,600.

Attorneys in the case, which arises from one of the most notable Katrina tragedies, were prevented from commenting by a gag order imposed by Judge Jerome Winsberg.

The Manganos remained free on bond Wednesday. They had originally been arrested on 34 counts of negligent homicide, but the grand jury added a 35th count in its indictment, representing a body that was found later. The grand jury also added the cruelty counts. The Manganos will be formally booked on the cruelty charges on Oct. 4, Winsberg said.

Since their arrests, the Manganos’ attorney, James Cobb, has gone on the offensive, recently filing a legal demand seeking to have a judge name several public officials and agencies as co-defendants in a civil lawsuit pending against St. Rita’s. Cobb has stressed that the facility never flooded before Katrina and the Manganos worried that an evacuation would kill some of their elderly and frail patients.

The district attorney’s office and the judges in tight-knit St. Bernard Parish recused themselves from the case. Winsberg is a retired criminal court judge from New Orleans. Louisiana Attorney General Charles Foti’s office is handling the prosecution.

Cobb had asked Tuesday that Foti and his office be removed from the case, in part because the Manganos have filed a civil suit against Foti and other state officials. But Winsberg rejected Cobb’s request Wednesday.