Man found guilty of involuntary homicide of dive buddy over 2020 Gozo accident

Arthur Castillo, a company director from Sliema, is found guilty of the involuntary homicide of Christine Gauci through negligence

Christine Gauci
Christine Gauci

A man has been found guilty of the involuntary homicide of his dive buddy, who lost her life during a dive at Mgarr ix-Xini, Gozo, in January 2020

60-year-old Arthur Castillo, a company director from Sliema, had been charged with involuntarily causing the death of Christine Gauci through negligence.

The victim was 35-year-old Christine Gauci, an AFM soldier from C (Special Duties) Company, who had enlisted with the British Army and deployed to Afghanistan, before returning to Malta and re-joining the AFM. Gauci was a diving instructor and would also free dive in her spare time.

Castillo, a long-time friend of the victim, had planned a dive with Gauci and four other friends on the day in question. He had released a statement during the investigation into Gauci’s death, explaining that she had bumped into him on the Gozo ferry before the dive, and had told him that she had been awake for the preceding 20 hours because of work duties.  

Castillo’s girlfriend had tried to convince the victim not to dive, he recalled, but Gauci had brushed this off, saying the cold water would revitalise her senses.

Two other diving pairs also took part in the dive. Not long after going underwater, at a depth of around 16 to 18 metres, Gauci had appeared to have encountered buoyancy problems, which Castillo had assisted her in recovering from. Using hand signals, he had asked whether they were going to call off the dive and surface, but Gauci had signalled that she wanted to continue, Castillo said in his statement.

The divers had descended to a depth of 28 metres, when the problem was encountered a second time and Castillo had pulled his buddy down, this time emptying excess air from her buoyancy control device. 

At one point during the dive, in a small underwater cave one of Gauci’s fins had become entangled in a fishing net, Castillo said, from which he had helped cut her free. Gauci had again communicated her intention to continue with the dive, he said.

On his suggestion, the pair had then ascended to a depth of around 15 metres, before turning towards Mgarr ix-Xini. Gauci’s buoyancy problems made a third appearance and so, in a bid to stop her ascending uncontrollably to the surface, Castillo had shifted two 1kg lead weights from his weight belt onto hers and Gauci had also picked up a heavy rock from the seabed.

Gauci had again communicated to her buddy that she wanted to continue with the dive, he said. 

Castillo explained how, suddenly, while he had been looking in another direction, Gauci had shot towards the surface before he could reach her. He saw the rock she had been holding sinking past him. Together with the other divers, Castillo had ascended to a decompression depth of eight metres, at which point he could no longer control his buoyancy either due to the absence of the two kg weights that he had given to Gauci.

An emergency ascent to the surface was carried out, at which point Castillo explained that he then spotted a person some distance away climbing out of the water, wearing a similar dry suit to Gauci’s. Thinking it was her, he swam in that direction, only to realise that it was another diver. 

The divers then started looking for Gauci, who was found face-down in the water near the rocky shore. Her eyes had rolled back in her head and there was foam in her mouth, he recalled. Their attempts to inflate her dry suit to help bring her on board an AFM vessel were unsuccessful as there was no air left in her tanks.

A diving equipment specialist had testified that Gauci’s twin air tanks had been completely emptied, remarking that this was a “cardinal error” that no diver would make, as they aim to have at least 50 bars of air left at the end of the dive.

Gauci’s spare cylinder had been untouched. She had not signalled to her dive buddy that she needed to share his air supply - which would also mean they would have to surface. Neither had she carried out a free ascent to the surface, while continuously breathing out to avoid barotrauma to her lungs.

Had Castillo followed his buddy to the surface there would have been two incidents, said the experts, concluding that Gauci might have suffered a cardiac arrhythmia which caused shortness of breath, leading to an instinctive quick ascent to the surface in search of air.

The specialist explained that Gauci had been tired before diving and had been using a dry suit that was too big for her, causing it to trap too much air. Besides being too large, the suit was also defective. She had not been trained on how to use a dry suit or maintain its buoyancy.

In his report to the magisterial inquiry, a doctor specialising in hyperbaric medicine also concluded that a combination of fatigue, an ill-fitting dry suit which the victim had not been trained to use and compressed air “supplied by an unlicensed operator with questionable maintenance on compressor,” were all factors in the fatal accident. 

With regards to Gauci’s dive computer, he noted that “although the diving computer’s setting is not overtly dangerous in itself, its setting at its most aggressive setting speaks to the diver’s general demeanour towards risk taking.”

However, the report also concluded that negligence and omissions were evident from Castillo’s side. “The whole scope of the diving buddy system is for the two divers to be close to each other to assist each other in any untoward event during the dive. The assumption that Ms. Gauci was safe on the surface and swimming back to shore, when no such contact and reasoning was made between the two divers, proved to be highly significant as it ensured the omission of a rescue attempt.” 

Magistrate Simone Grech observed that although Castillo had done what was required of him as a dive buddy for the majority of the dive, he had failed to do so during the final part of the dive. He had assumed that Gauci was swimming to the surface, had only seen her grasping her Nitrox 50% decompression cylinder and had not re-established eye contact with her. At that late stage in the dive, he had stopped asking her how much air she had left, despite having been monitoring her high rate of air consumption earlier on.

From her dive profile, it was established that only 20 minutes into the dive, at a depth of 10 metres, Gauci had already consumed 70 bars of the 200 she had started off with. The last time Castillo had checked with Gauci, she had 110 bars left, after which they spent 25 minutes ascending before the final incident.

They had not taken into account the fact that Gauci was using an open circuit scuba diving apparatus, whilst Castillo had been using a closed-circuit rebreather system, which created a discrepancy that would persist throughout the dive.

It was noted that as Castillo had been using a closed-circuit rebreather system “he was not in the right frameset of checking on his open circuit buddy; seeing he had no issues with length of gas supply, it was not within his procedures during the dive or second nature to his skill set to check his buddy’ s different and finite air supply.”

The court noted that the report specified that Castillo’s claim of being unable to follow Gauci as she ascended because he needed to decompress had been disproven by his decompression computer. “A two-minute deco obligation at five minutes is never an impediment to seek a lost diving buddy,” the report read.

The accused had made many assumptions in the circumstances surrounding the dive, said the court, ruling it to be evident that Gauci had been in difficulty and that Castillo had an obligation to ensure his dive buddy was safe and not simply to assume that she was safe.

Magistrate Simone Grech, presiding the Court of Magistrates in Gozo said she was morally convinced that the accused’s failure to carry out a rescue attempt while assuming that Gauci was safe was negligent and had contributed to Gauci’s tragic death. 

The court said that the tragedy could have easily been avoided by the accused, “had he exercised the caution and prudence evidently needed in the circumstances.”

Although the evidence had established an element of contributory negligence on the part of the victim, this did not in any way exonerate the accused of criminal responsibility for what happened, ruled the court.

Castillo was handed a two-year prison sentence, which was suspended for four years and ordered to pay two thirds of the costs of appointing experts to the inquiry.

Inspector Josef Gauci prosecuted.