Salvador and Mabel Mangano are also charged with 24 counts of cruelty to the elderly or infirm.
Prosecutors told the jury during opening statements Thursday that the Manganos failed to evacuate 59 frail, elderly residents from the St. Rita nursing home in St. Bernard Parish, despite ample warnings that the hurricane was getting stronger, USA Today reported Friday.
Thirty-five residents -- some strapped to their beds or attached to feeding tubes -- drowned when a wall of water filled the nursing home in 20 minutes.
Expected to testify is coroner Bryan Bertucci, who said he called Mabel Mangano twice the day before Katrina hit land and offered two buses to evacuate residents. Bertucci said she declined his offer.
However, defense attorney John Reid argued the Manganos didn't evacuate the residents because they weren't ordered to and because they thought moving the patients would endanger them, the USA Today report said.
The couple stayed in the home, they thought was on safe, high ground, with their own relatives and evacuated patients by boat when the floodwaters poured in, he added.