IOWA CITY, Iowa — In a surprising reversal, federal prosecutors on Wednesday abandoned their 12-year pursuit of the death penalty for a woman convicted of helping kill five people, including two children, in Iowa to protect her boyfriend's drug business.

The reversal in the 1993 slayings comes ahead of a second sentencing hearing for Angela Johnson, one of only two women on federal death row. The U.S. attorney's office in Cedar Rapids announced the decision in a court filing and a spokesman declined to comment.

Johnson, 50, will be sentenced to life in prison without the possibility for parole.

Johnson, who is at a federal prison in Carswell, Texas, reacted with "immense relief and gratitude to the government" after learning about the decision, said one of her attorneys, Michael Burt of San Francisco.

Johnson was convicted of being an accomplice as her boyfriend, methamphetamine kingpin Dustin Honken of Mason City, killed two former dealers who had been cooperating with a federal investigation into him, 32-year-old Terry DeGeus and 34-year-old Gregory Nicholson; Nicholson's girlfriend, Lori Duncan, 31; and Duncan's daughters, ages 10 and 6.

A jury in 2005 had given Johnson four death sentences, making her the first woman on federal death row in decades, but those were thrown out in 2012. A new sentencing hearing was scheduled for March.

Prosecutors said Johnson posed as a saleswoman to get into Duncan's home days before Honken was to plead guilty to drug charges. Honken and Johnson forced Nicholson to make a videotaped statement exonerating Honken, then took him, Duncan and her children to a field where they were shot in the back of the head, according to prosecutors. Months later, Johnson lured DeGeus, a former boyfriend, to a secluded location where Honken shot him and beat him with a bat, prosecutors said.

The victims' bodies weren't found until 2000, when Johnson, then jailed on drug charges, drew a map for an informant to a shallow grave near Mason City.

Iowa doesn't have the death penalty, but federal prosecutors said in 2002 that they would seek the punishment. Honken, who was convicted at a separate trial, is on death row in Terre Haute, Indiana.

U.S. District Judge Mark W. Bennett overturned Johnson's death sentence in March 2012, saying Johnson's lawyers failed to present evidence about her brain and personality impairments that could have been mitigating factors.

Johnson's lawyers met with the Justice Department's capital review committee earlier this year to try to persuade them to back off their pursuit of capital punishment. Burt said they made a "really strong and persuasive case" but were still surprised to learn of the reversal late Tuesday.

Johnson's lawyers stressed that many of the victims' families didn't want to go through another hearing and that Johnson wasn't accused of being the shooter. Also, they said expert testimony developed after the trial shows Johnson suffered from a brain disease that impaired her ability to weigh actions and had mood and personality disorders.

"I can't say enough about how much I respect Judge Bennett and the government for realizing this is not a case they should seek death in," he said. "It's really remarkable that they would reach that decision."