One of the chilling ransom notes sent to Nancy Guthrie’s heartbroken family included a disturbing apology for accidentally killing her, according to a dramatic new report.

The disturbing Feb. 6 email was sent to TMZ from the same IP address as earlier blackmail letters that were packed with eerie details about the night Guthrie — mother of “Today” host Savannah Guthrie — was snatched from her Arizona home, including what she was wearing, sources close to the case told Air Mail.

The purported abductor had initially demanded $4 million in bitcoin in a Feb. 2 note, described Guthrie as “safe but scared,” and spelled out terms for an exchange — convincing investigators they were dealing with the real kidnappers rather than sick internet pranksters.

However, a follow-up note on Feb. 6 opened with a bizarre, rambling “apology” for her accidental death, the outlet claimed.

It then suggested the 84-year-old kidnap victim’s body could be returned for a price, though no specific amount was given, the outlet’s sources said.

The ransom note was credited with shifting the investigation from a kidnapping case to one of potential homicide.

It also sparked the emotional response from Savannah and her siblings, who took to Instagram the next day in a 20-second video saying they had “received your message and we understand.”

She later begged the abductor to “return our mother to us,” adding that her return is “very valuable to us” and that “we will pay.”

After the Air Mail story was published, TMZ reported that the ransom note it received did not say that Guthrie was dead or contain an apology.

TMZ described the the notes it was sent as being from someone who claimed to know who kidnapped Nancy and where she was — but the author denied being the abductor himself.

Guthrie has been missing since Feb. 1 after authorities believed she was kidnapped from her Tucson home.

A barrage of ransom notes flooded her family and media outlets, including several sent to TMZ, after her disappearance, with investigators sorting the messages into three categories — “the good, the bad, and the ugly” — as they combed through every line and chilling demand, sources told the outlet.

Notes with specific information about Guthrie were deemed “good,” while the one referencing her accidental death was labeled “bad,” the insiders said.

Savannah admitted in a “Today” interview earlier this year that most of the ransom notes sent to her family were fakes — but she added, “I believe the two notes that we received that we responded to, I tend to believe those are real.”

No arrests have been made and no new leads have manifested as the investigation into the mysterious disappearance continues.