On the morning of November 4, 1980, ten-year-old Elisa Vera Nelson was riding her bicycle to Palm Harbor Elementary School in Palm Harbor, Florida, after a dental appointment when she was abducted about 100 yards from campus by 27-year-old Larry Eugene Mann. Mann discarded her bicycle in a ditch and drove her to a nearby orange grove, where he beat her, stabbed her multiple times, and crushed her skull with a concrete-encased pole, causing her death. Her body was discovered the following day, shocking the semi-rural community. Nelson was survived by her parents and 12-year-old brother.
Mann had a prior 1973 burglary conviction in Mississippi in which he forced a young girl to perform oral sex on him; he served four years of a nine-year sentence and was paroled in 1978. On the afternoon of the murder, Mann attempted suicide and was hospitalized after police intervened; he told officers he had "done something stupid," which they initially misinterpreted as referring only to his suicide attempt. Four days later, on November 8, 1980, Mann's wife found a bloodstained note belonging to Nelson in his truck. Police obtained a search warrant, and Mann was arrested on November 10, 1980. Fingerprint evidence further connected him to the crime.
Mann was charged with first-degree murder on the day of his arrest. His trial began March 16, 1981, before a Pinellas County jury, which found him guilty of kidnapping and murder on March 19, 1981, and recommended the death penalty the next day. Circuit Court Judge Philip A. Federico formally sentenced Mann to death on March 26, 1981, along with a 99-year sentence for kidnapping, describing the murder as "heinous, atrocious, and cruel."
Mann's death sentence underwent multiple rounds of appeal and re-sentencing. The Florida Supreme Court vacated his original death sentence in 1982, and he was re-sentenced to death in 1983; that sentence was upheld by the Florida Supreme Court in 1984 and the U.S. Supreme Court in 1985. An execution scheduled for February 4, 1986, was stayed the night before by a federal judge, and in 1987 the 11th U.S. Circuit Court of Appeals overturned the sentence. A third jury recommended death in 1990, and Judge James R. Case imposed a third death sentence, which was upheld through further state and federal appeals into the 2000s.
A new death warrant was signed in March 2013, and after final appeals were denied by the Florida Supreme Court and the 11th Circuit, the U.S. Supreme Court rejected a last appeal on April 10, 2013. Mann was executed by lethal injection that evening at Florida State Prison, with time of death recorded at 7:19 p.m.
Mann was also named a suspect in at least three to four unsolved 1970s Mississippi homicides—Rose Marie Levandoski, Janie Sanders, Debra Gunter, and Clara Turk—cases sharing similarities with Nelson's murder, though as of 2022 those cases remained unsolved and investigators noted the possibility another person was responsible. Palm Harbor Elementary School later named a mural and reading corner after Nelson, and in 2019 a newly built elementary school on the site of the old campus was named Elisa Nelson Elementary in her memory.