The owners of a nursing home where 35 people died in the flooding that followed Hurricane Katrina pleaded not guilty Wednesday to charges of negligent homicide and cruelty to the infirm.

Salvador and Mabel Mangano had been booked with negligent homicide shortly after the Aug. 29, 2005, storm, but they were not charged until late last month because a grand jury could not convene any earlier in badly damaged St. Bernard Parish.

The Manganos, owners of St. Rita's Nursing Home, were allowed to remain free on bail following the arraignment hearing before State District Judge Jerome Winsberg.

More than 30 lawsuits have been filed against the couple by patients injured at the nursing home and the families of people who died there.

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The Manganos have sued the government, saying federal, state and local officials failed to keep residents safe. The couple argue that their hurricane plan — keeping frail residents in place with food, water and generators rather than risking their lives by moving them — was responsible, and that nobody would have died had the levees held.

The judge has imposed a gag order barring attorneys, the Manganos and witnesses in the case from talking with the media. However, he did allow defense attorney James Cobb, who represents Salvador Mangano, to read a statement after the hearing saying he planned "a very aggressive defense."

"In our opinion, for more than a year, the office of attorney general of Louisiana has, without factual support, pursued the Manganos," Cobb said.

Prosecutors said they could not comment.