Katy Devlin’s murder at the excavation site becomes legible through two converging lines of evidence: a history of unexplained illness that raises suspicion of poisoning, and a missing archaeological trowel and blood traces that locate the killing in the finds shed. The investigation links the family’s unanswered questions about Katy’s illness to a specific sequence at the dig, but the evidence presented here does not identify the murderer or resolve every uncertainty about access to the sheds.

Background and Suspicion

During questioning, Jonathan Devlin insists that he does not know what happened to the children who disappeared years earlier and says his concern is finding out who killed Katy. The investigators temporarily set that earlier matter aside and turn to Katy’s medical history. Her records show four years of unexplained gastric illness, ending in the spring, when she told her ballet teacher that it would stop and then recovered. The medical examiner found no sign of an underlying condition that would explain the illness.

Cassie Maddox presents poisoning as the investigators’ explanation for that pattern. The inference rests not on a named poison recovered from Katy, but on the contrast between years of illness and its sudden end, together with the medical examiner’s findings. She argues that the person responsible would have needed regular access to Katy and her trust. Katy had been given another chance at ballet school, and Cassie suggests that her refusal to continue taking whatever had made her ill may have threatened to expose the arrangement. A few months later, Katy was dead. These details make her illness part of the murder investigation rather than a separate medical mystery, while the proposed connection remains an investigative case rather than a finding established by the medical record alone.

Jonathan’s response changes the investigators’ reading of the exchange. As Cassie describes Katy’s illness and the possibility of poisoning, the anger leaves his face and he turns visibly pale. Rob Ryan interprets this reaction as recognition: Jonathan knows something. Ryan then asks whether Jonathan is protecting his wife, Margaret Devlin, and offers help if the family’s effort to remain together is the reason for his silence. Jonathan replies that Margaret loves their daughters, but the exchange ends before he completes his defense. The scene raises the possibility of family knowledge without establishing that Margaret poisoned Katy or that Jonathan knew who killed her.

The Missing Trowel and the Shed

The investigation later focuses on a missing tool from the excavation site. On the night Katy died, a trowel disappeared from the locked finds shed. It had a leaf-shaped metal blade fixed to a wooden handle five or six inches long, narrowing toward the blade and rounded at the end. The handle bore the burned initials of its owner, Sean Callaghan, who said he had left it in the shed at five thirty on Monday evening and forgotten it. Dr. Cooper’s description of the implement used in the assault matched the trowel.

Because the trowel’s presence in the finds shed was not expected, Rob Ryan treats it as a possible weapon of opportunity and the shed as a possible primary crime scene. The distinction matters: the tool’s disappearance and its match to the description give investigators a route into reconstructing events, but do not by themselves establish who took it or when it was used. Ryan directs Sophie and her forensic team to begin their examination in the finds shed.

Access narrows the inquiry without immediately settling it. Ian Hunt, Mark Hanly, and Damien Donnelly had keys to the finds shed. The investigators cannot rule out Callaghan, since his account of leaving the trowel there might be false. Hunt and Hanly had cars, so either could have transported or concealed Katy’s body in a vehicle. Callaghan and Donnelly were not known to have cars, which led Ryan to consider a nearby hiding place, probably on the site, if one of them was involved. These are conditional lines of inquiry, not conclusions about any individual’s guilt. The team searches for the trowel, a bloodstained plastic bag, and evidence of both a primary and a secondary crime scene.

Forensic Confirmation and Reconstruction

The physical examination supplies the decisive change in the inquiry. Luminol reveals patterns on the finds-shed floor and lower shelving. Although the chemical can produce false positives, including from household bleach and copper, Sophie has the floor swabbed and confirms that the substance is blood. Rob Ryan realizes that Katy died in the shed where the team had already interviewed the killer. The finding transforms the shed from a plausible location into a confirmed crime scene, even though the identity of that interviewee is not disclosed in this account.

The investigators later tell Damien Donnelly that evidence from two sheds supports a more specific sequence: Katy was killed in the finds shed on Monday night and kept in the tools shed through Tuesday. There was no forced entry. The timing and movement between the sheds distinguish the place of death from the place where the body was concealed afterward. When Damien asks whether the investigators have found something in a shed, Ryan confirms that they found evidence in two, but withholds details. He explains that the absence of forced entry points toward someone with a key and names Mark, Dr. Hunt, or Damien as the possibilities under consideration; Hunt, Ryan adds, has an alibi.

Significance and Limits of the Evidence

The murder’s reconstruction proceeds by joining circumstantial and physical clues without treating them as interchangeable. Katy’s illness suggests a prolonged betrayal by someone with access to her; the missing trowel connects the excavation site to the assault; confirmed blood establishes the finds shed as the place of death; and evidence from the tools shed extends the sequence into Tuesday. Each discovery sharpens the account of what happened while leaving the question of responsibility open in the scenes covered here.

The sheds also give the investigation a concrete structure. A locked room, a tool whose owner says he forgot it, a small group of keyholders, and evidence of movement between two work spaces turn the site into a set of testable questions about access and timing. The case moves from the apparent privacy of Katy’s illness to the material traces of a crime committed within the excavation complex. Its central reversal is that the sheds where workers stored tools and finds had also preserved evidence of Katy’s death and concealment.