A New Orleans surgeon accused of killing four patients in the aftermath of Hurricane Katrina will not face trial, a grand jury has decided.
Dr Anna Pou has given up her private practice and now teaches
Prosecutors in New Orleans had sought to try cancer surgeon Anna Pou for murder and conspiracy to murder.
Dr Pou denied using drugs to kill patients at Memorial Medical Center after storm waters broke levees and flooded much of the city.
At least 34 people died at the hospital in the aftermath of the 2005 hurricane.
Patients at the 317-bed hospital spent four days stranded in floodwater, with no electricity, after Hurricane Katrina struck Louisiana.
Dr Pou was accused along with two nurses, Lori Budo and Cheri Landry, both of whom had charges against them - which they also denied - dropped in June.
The pair testified to the grand jury under legal guidelines that prevented their testimony from being used to incriminate them.
The Memorial Medical Center was cut off by floods for days
Lawyers for all three medical workers said they had worked heroically to treat patients instead of evacuating the hospital during the chaotic days after Hurricane Katrina struck.
Dr Pou and the two nurses were charged with four counts of second-degree murder.
They were accused of giving four patients - two in their 90s and two in their 60s - lethal doses of morphine and a sedative.
But all three protested their innocence and won support from within the local community.
"[The grand jury] concluded that no crime had been committed," New Orleans District Attorney Eddie Jordan said after the decision was made.
"And that is the decision of our grand jury, and I think justice has been served after due process."
In all, more than 970 people are known to have died in Louisiana in the aftermath of Katrina, and more than 200 in neighbouring Mississippi.