McMartin Preschool Tunnel Claims | Religious Tolerance

At a glance

The McMartin case became a prominent example of a multi-complainant preschool investigation.
Children gave differing accounts of trapdoors, underground rooms and passages.
Several searches found no confirmed tunnel system or matching openings in the concrete slab.
A later excavation interpreted buried features differently, producing a dispute that remains part of the case history.

Background

The McMartin Preschool prosecution began in California in the 1980s and lasted several years. It attracted extraordinary public attention, involved numerous allegations, and ended without a conviction. A broader outline is available in the McMartin case overview.

During interviews, some former pupils described being taken through concealed openings into underground spaces. Accounts varied considerably: proposed entrances appeared in different classrooms, bathrooms, play areas and an outdoor playhouse. Some narratives also included improbable forms of travel and distant locations.

The tunnel question became central because physical confirmation could have supported at least one element of these accounts. Conversely, an absence of entrances, structural supports or disturbed soil would weaken the claim that such a system existed.

Reading this archive responsibly

This page discusses allegations involving children without reproducing explicit testimony. Allegations, interview statements and physical findings are distinct categories of evidence. The case should not be used to dismiss genuine reports of abuse or to accept extraordinary claims without corroboration.

Reported entrances and trapdoors

Investigators recorded several proposed access points. The reports did not converge on one shared entrance:

Inside the building

Locations included corners of several classrooms, spaces beneath bathroom sinks and points along walls. The accounts proposed passages toward neighboring property or rooms below the school and play yard.

Outside areas

Other reports placed access in the front or outer play yards, including a playhouse, a ground-level door, a ladder and a hole said to lead to a larger chamber.

The building stood on a poured-concrete slab. Investigators removed floor coverings and examined the places described by children. They reported no trapdoors, sealed openings or concrete repairs consistent with the proposed access points. The outdoor playhouse also stood on a solid slab, where inspection found no evidence of a former opening.

A repaired concrete slab ordinarily retains visible differences in texture, color or seams. The absence of corresponding repairs therefore became an important part of the physical-evidence assessment.

Searches of the property

March 1985 · Parent-led excavations

Parents first dug test holes and later used machinery to cut trenches near the building and across the adjacent lot. They found no tunnel, underground room, structural bracing or other physical confirmation.

March 1985 · Archaeological survey

A firm retained by the district attorney surveyed the area with conductivity equipment designed to identify subsurface changes. It detected former refuse deposits but reported no tunnels or rooms.

April 1990 · Further digging

A deep excavation was made beneath part of the building associated with several accounts. It did not reveal the alleged passages, rooms or access points.

1990–1993 · Manhattan Tunnel Project

A privately coordinated excavation interpreted several buried features as a possible passage, a tunnel and a room. Its lengthy report became the principal basis for later arguments that tunnels had existed.

Why the later findings were disputed

Critics of the private excavation identified several evidentiary problems. Some objects were not photographed in their original positions, some images were difficult to interpret, and no substantial shoring was found. In sandy soil, usable passages would generally require visible reinforcement to prevent collapse.

A consulting geologist did not find the observations sufficient to establish a tunnel. The company conducting ground-penetrating radar also reported that its scans did not demonstrate tunnels. Material characterized as fill reportedly contained refuse predating construction of the preschool, supporting the alternative interpretation that the features were old disposal pits or other earlier ground disturbance.

The competing conclusions should be represented precisely: one project interpreted soil features as tunnel-related, while other specialists and surveys did not regard the available physical evidence as confirmation of a tunnel system.

Interview evidence and memory

The case became influential in discussions of interviewing young children. Research reviewed in the archive indicates that repeated, leading or expectation-laden questions can affect a child's answers. A child may alter a response after inferring that an adult expects something different.

That principle does not mean children are generally unreliable or that their reports should be ignored. It means interview methods matter. Neutral prompts, careful documentation, avoidance of repeated suggestion and independent corroboration are essential when evaluating any allegation. See the archive's introduction to children, suggestion and interview evidence.

The play equipment called “tunnels”

The preschool did contain above-ground play equipment that children called tunnels: open-ended, brightly colored plywood boxes that could be arranged in different patterns and crawled through. This concrete detail may help explain how a familiar word or image entered later conversations, but it cannot by itself establish how any particular account developed.

Evidence-based conclusion

The available record does not establish that an underground tunnel network existed at the McMartin site. Multiple searches failed to locate matching trapdoors, slab repairs, reinforced passages or rooms. The later excavation's interpretation of disturbed soil remains contested and was not supported by the radar contractor or consulting geological assessment summarized in the source record.

The most cautious conclusion is therefore that the tunnel allegations lacked reliable physical corroboration. The episode remains useful as a study of interviewing practice, media attention, evidentiary standards and the care required when extraordinary claims arise in a child-protection investigation.

A separate case in Nottingham, United Kingdom, involved verified abuse within an extended family, followed by wider claims involving tunnels. Police examined reported locations and found no evidence that the proposed underground network existed. That history is summarized in the Nottingham case archive. The broader cultural setting is discussed on the ritual-abuse claims page.

Selected source record

John Earl, an article examining the McMartin tunnel claims in Issues in Child Abuse Accusations, volume 7, number 2, 1995.
Ellen Bass and Laura Davis, The Courage to Heal, third edition, 1994. Included here as an example of a publication citing the tunnel interpretation.
A 1994 sociological overview of the litigation, justice process and public response to the case.
Paul and Shirley Eberle, The Abuse of Innocence: The McMartin Preschool Trial, 1993.
E. G. Stickel, Archaeological Investigations of the McMartin Preschool Site, Manhattan Beach, California, Manhattan Tunnel Project report, 1993.
Contemporary archaeological, geological and radar records summarized in the source essay.