A strange story of his diving accident
“What began as a diving accident quickly escalated into a cross-border criminal investigation that left survivors accused of murder.”
In 2002, a recreational diving trip off the Croatian coast turned into a fatal incident that triggered a criminal investigation and the temporary imprisonment of two survivors, according to the account of Dan Frolec.
Frolec, then 32 and based in Prague, was part of a group of diving enthusiasts exploring coastal waters near Poganica Bay. The group included experienced divers and acquaintances from a diving club formed in the late 1990s.
During the trip, attention focused on a previously identified underwater formation described as a shallow hole, later understood to be a cave system with narrow tunnels and larger internal chambers.
On the evening of the incident, several members of the group entered the cave while others, including Frolec, remained on the boat. One diver, identified as Michael, surfaced briefly to retrieve additional equipment before returning alone to the cave. According to Frolec, this deviation from standard buddy-diving practice was not initially considered unusual, as it was assumed he would rejoin the others inside.
After a prolonged period, the remaining divers resurfaced without Michael. They reported abandoning further exploration due to poor conditions and inadequate equipment for cave diving. When it became clear that Michael had re-entered the cave alone, concerns escalated.
A subsequent attempt to locate him was unsuccessful, with limited visibility and hazardous conditions complicating the search.Emergency services were contacted, and Croatian coastguard personnel arrived the following morning. Despite reservations expressed by experienced members of the group regarding equipment suitability, two official divers attempted to enter the cave.
One diver remained outside while the other descended into the tunnel.The rescue operation resulted in a second fatality when the diver who entered the cave failed to return. A subsequent attempt by members of the original group to assist also proved unsuccessful due to deteriorating underwater visibility, likely caused by disturbed sediment within the confined environment.
Authorities later confirmed that both bodies were eventually recovered from the cave system. Conditions inside the cave, including low visibility and confined passageways, were identified as contributing factors in the fatalities.
Following the incident, Croatian police detained members of the diving group for questioning. Frolec and another participant, identified as Ivo, were separated from the group and subjected to further investigative procedures.
These included fingerprinting, blood sampling, and a polygraph test.According to Frolec, the line of questioning suggested that investigators were exploring the possibility of homicide. He states that authorities raised the prospect that Michael had been stabbed and questioned whether members of the group were responsible.
This marked a shift in the investigation from an apparent accident to a potential criminal case.Frolec and Ivo were subsequently designated as suspects and placed in custody. A judge ordered their detention for at least one month while the investigation continued, with the possibility of extended detention under Croatian law.
During this period, both men were held in prison alongside individuals accused of unrelated serious offences.Media coverage intensified the situation. Local reports published their names and alleged involvement in a murder, contributing to reputational damage and increasing psychological pressure during detention.
Frolec described the experience as disorienting and marked by uncertainty, particularly given the absence of formal charges .The investigation began to shift after additional evidence was reviewed. Testimonies from other divers challenged the initial theory of homicide, indicating that Michael had entered the cave alone and remained there for a period consistent with an accidental death.
Data from his diving computer reportedly showed that he had been alive for approximately 30 minutes while attempting to navigate the cave system.Attention also focused on red stains found on the group’s boat, which investigators initially considered potential blood evidence.
Frolec maintained that these marks were caused by mooring ropes. Subsequent DNA analysis confirmed that the stains were not blood, undermining a key element of the prosecution’s suspicion.Authorities later concluded that Michael’s injuries, initially interpreted as stab wounds, were likely self-inflicted in the course of distress within the cave environment.
The exact circumstances of his final moments remain unclear, though limited visibility and depleted air supply were considered significant factors.After nearly a month in custody, Frolec and Ivo were released without charges.
The case highlighted challenges in interpreting evidence in complex accident scenarios, particularly in hazardous environments such as underwater caves.In the years following the incident, Frolec stated that the experience had a lasting impact on his perspective, particularly regarding personal freedom and risk.
He later documented the events in The Cave: The True Story of Two Mysterious Deaths in an Underwater Labyrinth, detailing both the diving accident and the subsequent legal ordeal.The case also underscored the risks associated with cave diving, which requires specialised equipment, training and strict adherence to safety protocols.
According to Frolec’s account, deviations from these practices, combined with environmental hazards, contributed to a sequence of events that escalated from a recreational outing into a fatal incident and international legal case.
