Hennepin County prosecutors have declined to file charges against a nurse who gave two substantial overdoses of morphine to an assisted-living resident in Bloomington who later died, County Attorney Mike Freeman said Thursday.

Freeman cited a lack of evidence to prove either intent or negligence by the nurse.

The resident, identified by her family as Stella A. Pfeifer, 98, of Minneapolis, died of acute morphine toxicity in January after being given oral doses of the drug, two hours apart, that were 20 times the prescribed amount, the Minnesota Department of Health disclosed Tuesday. The incident took place at Nervana’s Caring Hands.

Health Department investigators blamed the nurse who administered the narcotic to Pfeifer, who raised a family in south Minneapolis while her husband worked as a roofer until his death at age 56.

But, Freeman said, it was “impossible to prove criminal wrongdoing.

“[The evidence was] insufficient that the overdoses were any kind of intentional act designed to kill her. And it was impossible to prove that this was not a mistake.” Freeman said his office wondered whether “we are getting into assisted suicide here. There is absolutely no indication of that here.”

The decision was met with disappointment by Pfeifer’s daughter, Jeanett Walsh, who said, “You would think a nurse would know more about what she’s doing. Why would you give her more morphine? She wasn’t in pain.”

Walsh said it’s clear to her that the nurse “took Mother’s life. Well, it’s over and done with.”

Bloomington police referred the case to prosecutors knowing “we have to prove it’s a crime and not just a mistake,” Deputy Chief Vic Poyer said earlier this week.

After Freeman’s decision was announced, Poyer acknowledged that his department “didn’t meet the level that the county attorney felt rose to a criminal matter.”

The 39-year-old nurse did not cooperate with either investigation, police and the Health Department said.

Records at the state Board of Nursing showed no prior complaints against her.

Pfeifer received the morphine at 8 p.m. and again at 10 p.m. on Jan. 15, “was sedated by the medication overdose and did not regain consciousness,” the Health Department report said. She died the next afternoon.

Relatives told a state investigator that they questioned the nurse about the need for the narcotic, pointing out that she did not seem to be in pain, but acknowledged she was having trouble breathing.

According to the state report, Pfeifer had been living at the home for about two years when she was hospitalized for pneumonia for a week, and then returned to the home. On the night of Jan. 15, the nurse gave Pfeifer morphine, which was to be administered to address her pain and shortness of breath, but “an error was made when calculating the dosage,” the report said.

The home’s owner said she had not provided any training to the nurse, noting that the nurse had graduated within the previous year and had recent training.

The home’s operator, Nervana Ramnarain Ramdyal, did not return calls for comment regarding either the Health Department’s finding or the county attorney’s decision.

Walsh said Ramdyal fired the nurse immediately after her mother died.

Ramdyal was “extremely nice to Mother,” Walsh said. “It’s an extremely nice home.”