Thomas Overton

The backstory

Background

Susan Michelle MacIvor, 29, and her husband, Michael MacIvor, 30, lived in a two-story stilt house in a gated community beside a private airstrip on Tavernier Key, in the upper Florida Keys, according to the Florida Supreme Court. Susan MacIvor was about eight months pregnant with the couple’s first child.¹³ Overton worked at an Amoco station “only a couple of minutes away” from their home, the court wrote.¹ News reports say he knew the couple.¹⁴¹²

The crime

The couple were last seen at a childbirth class that ended at about 9 p.m. on Aug. 21, 1991. The next morning, concerned co-workers and a neighbor found them dead in their home.¹ According to the court, the phone wires outside the house had been “recently cut with a sharp instrument,” a ladder was propped against the balcony outside the nursery, and the sliding glass doors to the master bedroom and the nursery were open.¹

Michael MacIvor’s head had been wrapped in masking tape. The medical examiner testified that he had suffered a severe blow to the back of the head and an abdominal injury that “could have been inflicted by a strong kick,” and that he died of “asphyxiation by ligature strangulation (rope).”¹ Susan MacIvor was found naked on a white comforter, her wrists and ankles bound with belts, tape and clothesline rope, with a garrote made from “a necktie and a black sash” around her neck. The medical examiner concluded that she “had been sexually battered” and had been strangled.¹²

The medical examiner found that the couple’s unborn son would have been viable and that he “lived approximately thirty minutes after his mother died.”¹²

The investigation and the DNA

Investigators found semen stains on the fitted sheet and mattress pad.¹ Overton’s name came up at a brainstorming session in May 1992, the court wrote, because he was a known “cat burglar” who worked nearby and had been a suspect in another 1991 killing; he was never arrested in that case.¹² In 1993 an analyst at the Florida Department of Law Enforcement developed a DNA profile from the stains, but “no match was made at that time.”²

In late 1996, Overton, then under surveillance, was arrested during a burglary in progress, according to the court. He refused to give a blood sample. Days later, in jail, he “made two cuts into his throat” with a razor blade; police were unsure whether it was a suicide attempt or an escape ploy.¹ Blood on the towels led police to obtain a court order for his blood. In November 1996 the state analyst compared it with the profile from the bedding and found “an exact match at each locus,” the court wrote, with a probability of a random match “in excess of one in six billion.”¹² In 1998, a private lab using a newer method, short tandem repeat testing, matched him at all 12 loci tested; its analyst put the chance of a random match at “1 in 4 trillion Caucasians.”¹

The trial

Two jail inmates testified that Overton had described the crime to them, according to the Florida Supreme Court.¹³ One testified that Overton told him he cut phone lines, wore gloves and carried a “kit” on burglaries, and that he “had to waste — waste somebody in the Keys.”¹ The other, who met Overton in the Monroe County Jail in May 1997, testified that Overton described striking Michael MacIvor, binding the couple, raping and strangling Susan MacIvor because he “doesn’t leave any witnesses,” and then strangling Michael. That inmate testified that Overton wanted him to tell police that another inmate had supplied the details, to create reasonable doubt.¹

The defense argued that a sheriff’s detective had planted Overton’s semen on the bedding, using semen obtained from a former girlfriend, who had died in 1994. The defense said the detective’s motive was an internal affairs complaint Overton had filed against him; the detective denied the claim and had been cleared in the internal investigation.¹³ A defense test found traces of Nonoxynol-9, a spermicide; a chemist testified that it could not be distinguished from the detergent form of the compound on the sheet.¹ Defense lawyers also cross-examined the serologist who collected the evidence about how it was handled, including that he took swabs to his home and kept them in his home refrigerator, and dried the bedding at his home, according to the 11th Circuit.³

The jury found Overton guilty on all counts on Feb. 10, 1999.⁶¹

The penalty phase

Overton declined to present any mitigation and barred his lawyers from presenting or arguing it, the Florida Supreme Court wrote. The state presented only victim-impact evidence.¹ Explaining his decision, he told the court, “I didn’t commit the crime,” and said, “I trust the appellate system.”¹ He also said he would not “put my family and friends though this stuff.”¹ The court held that his waiver was knowing and voluntary.¹

The jury recommended death by a vote of 9 to 3 for the murder of Susan MacIvor and 8 to 4 for the murder of Michael MacIvor.¹ On March 18, 1999, Monroe County Circuit Judge Mark H. Jones sentenced him to death for each murder.⁶

Why the court chose death

The judge found five aggravating circumstances for each murder, listed in full below: that Overton had been convicted of another violent felony, the contemporaneous murder of the other victim; that the murders were committed during a sexual battery and a burglary; that they were committed to avoid arrest; that they were especially heinous, atrocious or cruel; and that they were cold, calculated and premeditated.¹²⁷ The sentencing order, as quoted in news reports, found that the crime-scene evidence “shows beyond a reasonable doubt that a fundamental part of the Defendant’s criminal plot” was a plan to avoid detection.¹⁴

The judge found no statutory mitigating circumstances. Reviewing the record and a limited presentence report, he considered Overton’s family background, military and employment records, possible substance abuse and possible mental health problems, and found none to exist as mitigation.¹ He found two nonstatutory mitigating circumstances: that Overton “will be incarcerated for the rest of his life with no danger of committing any other violent act,” given little weight, and his courtroom demeanor and behavior, given some weight.¹ He concluded that “the scales of life and death tilt unquestionably to the side of death.”¹²

The direct appeal

On Sept. 13, 2001, the Florida Supreme Court unanimously affirmed the convictions and sentences.¹ It held that one prospective juror should have been excused for cause but that the error was not reversible, and it rejected claims about discovery of the 1998 DNA testing, the denial of an additional defense chemist and other trial rulings.¹ It wrote that the defense had failed to produce “a scintilla of evidence that [the detective] planted the seminal fluids.”¹

Overton challenged the heinous, atrocious or cruel finding as to Michael MacIvor. The court upheld it, concluding that he was conscious when the strangulation began, and noting that “strangulations are nearly per se heinous.”¹ It held that the trial court had properly considered the mitigation in the record, and on its own review found the evidence sufficient and the death sentences proportionate.¹ The U.S. Supreme Court declined review on May 13, 2002.⁶³

State postconviction

In postconviction proceedings, Overton’s lawyers raised 13 claims, including that his trial lawyers failed to contest the newer DNA method at a pretrial hearing, failed to impeach the inmate witnesses and failed to pursue an alibi, and that the state withheld evidence.² After a hearing on some of the claims, the circuit court denied relief in February 2005.²⁶ On Nov. 29, 2007, the Florida Supreme Court affirmed. It found that counsel’s limited role in the DNA hearing was a reasonable strategy and caused no prejudice, because “the chain of custody was intact” and the newer testing met the standard for scientific evidence.²³ It also affirmed the denial of DNA testing on hairs found on the binding tape, holding that because there was no way to show when the hairs were deposited, a non-matching result would not create a reasonable probability of acquittal, and it denied a habeas petition that challenged the chain of custody.² The court affirmed the denial of later successive motions in August 2013, and later denied relief under the Hurst decisions because his sentences became final before Ring v. Arizona, according to Tracking Florida’s Death Penalty.⁸

Federal habeas

A federal district court denied Overton’s habeas petition in 2016 as untimely and, alternatively, on the merits.³⁸ On June 26, 2025, after granting rehearing and replacing an earlier opinion, an 11th Circuit panel held the petition timely but affirmed the denial of relief.³⁹ The panel wrote, “We are troubled by [the serologist’s] handling of the DNA evidence in this case,” but held that Overton had presented “no evidence in the state postconviction proceedings that the DNA evidence had been tampered with” or that it had meaningfully degraded.³ It held that the undisclosed fact that the state lab had rejected evidence the same serologist submitted in another case was cumulative of the impeachment at trial.³

His lawyers asked the U.S. Supreme Court to review the case, arguing that the serologist’s “collection and storage of the DNA evidence fell below acceptable scientific standards” and that federal courts’ deference to state rulings is unconstitutional.⁵ The court denied review on Feb. 23, 2026.⁴

The death warrant

DeSantis signed the warrant on Oct. 21, 2026.⁸¹² The News Service of Florida reported that it sets the execution for 6 p.m. Nov. 18 at Florida State Prison; the Death Penalty Information Center, the Miami Herald and Tracking Florida’s Death Penalty give the date as Nov. 19.^121310118 Tracking Florida’s Death Penalty reported that Overton and Jesse Guardado, whose execution is set for Nov. 5, are the two prisoners on death watch in Florida.⁸ The sources reviewed do not describe any litigation filed since the warrant was signed.

Personal backstory

Early life

Overton was born on Nov. 5, 1955.⁶ Because he declined to present mitigation, the court record contains little about his life.¹ His trial lawyer told the court that the defense had tried to pursue his family background and possible mental mitigation and had looked into his military and school background, and that there “were some allegations of drug abuse.”¹ An investigator’s affidavit said that his mother, at his request, would not speak with the defense.¹ Tracking Florida’s Death Penalty, a publication that follows Florida capital cases, wrote that he survived the Dozier School for Boys, which it described as an abusive “reform” school.⁸ The sources reviewed do not say where he grew up.

Mental health

The trial judge considered possible mental health problems and found no mitigation in that area.¹ No diagnosis appears in the sources reviewed.

Life before the crime

Overton worked as a service-station clerk in Tavernier, according to news reports, and at an Amoco station near the MacIvors’ home, according to the court.¹⁴¹ Detectives described him as a “career burglar,” the Miami Herald reported.¹¹ Rejecting mitigation, he told the court that his “back history, my drug abuse and everything” was “an excuse that somebody who’s guilty would use.”¹

Life in custody

Overton has been in custody since his arrest in 1996.¹ In 2001 he was convicted of the 1996 burglary and sentenced to life, which the Miami Herald reported prosecutors sought to keep him in prison if the murder convictions were overturned.¹¹ The Commission on Capital Cases recorded one disciplinary infraction, for spoken threats, at Union Correctional Institution in 2002.⁶ He is 70.¹¹ The sources reviewed contain no statement from Overton since the warrant was signed.