In 2005, she was found guilty of involvement in the murder of five people in the State of Iowa in the 1993 attempt to derail a federal methamphetamine investigation. Iowa is one of fourteen US states without a capital punishment law. The jury that convicted her also handed down four death sentences. The presiding judge stated "I am troubled by the lack of certainty in the record concerning the precise involvement of Angela Johnson in these crimes". Under federal law, the judge is bound by the jury's verdict. In July, 2007, the U.S. Court of Appeals for the Eighth Circuit upheld the conviction, finding sufficient evidence to conclude that Johnson had participated in the murders.
Her former boyfriend, Dustin Honken, is currently on death row, also convicted of the murders. Although it was Honken who actually pulled the trigger, killing three adults and two children, Johnson received the death penalty for only four of the victims, while Honken was sentenced to death for only the two children.
Johnson, who lured four of the victims to their death by posing as a lost sales person in need of a phone book, gained entrance into the victim's home, allowing access for Honken. Honken then videotaped a forced confession from one of the victims in hopes of exoneration from a previous drug charge. Afterwards, the victims were taken to a remote location before being murdered. The fifth victim, who previously dated Johnson and allegedly owed drug money to Honken, was also baited by Johnson when she requested they meet at a local country club where she was working. They then drove to a local farm where Honken was waiting with a loaded handgun. The Court of Appeals described her participation thus: "[T]he killings resulted from her substantial participation in the murders; namely, that she procured the murder weapon, participated in the hunt for Nicholson, employed a ruse so that she and Honken could gain entry to the Duncans’ residence, bound and gagged at least one of the victims, and exploited her relationship with DeGeus to lure him to the remote location where he was killed." 
Johnson, who had a child from a previous marriage, was also pregnant by Honken at the time of the murders.
On March 23, 2012, Federal Judge Mark W. Bennett vacated Johnson's death sentence, citing a failure to introduce evidence about her mental state from an "alarmingly dysfunctional" defense team. Her punishment phase will either be re-heard in front of a new jury or she will be sentenced to life without parole. The vacating of her death sentences did not affect her convictions in the case.
- "Woman sentenced to death". Associated Press. 2005-12-21. Retrieved 2008-06-05.
- "Death Penalty Policy By State". Death Penalty Information Center. 2008. Archived from the original on 12 June 2008. Retrieved 2008-06-03.
- U.S. v. Angela Johnson. "Court Opinion" (PDF). US Court of Appeals.
- "Angela Johnson." Federal Bureau of Prisons. Retrieved on October 14, 2010.
- "Judge removes 1 of 2 women from federal death row". CBS.com. Associated Press. March 23, 2012. Retrieved 23 March 2012.
- Death in Iowa at The Malefactor's Register