The scuba diving instructor who was teaching the class in which 12-year-old Dylan Harrison died has resigned from his position as Assistant Chief Deputy of the Collin County Sheriff’s Office in Texas.
William Armstrong, a NAUI-certified instructor, was supervising a class of eight divers with his divemaster Jonathan Roussel, when he lost sight of Dylan during a descent to a 5m-deep training platform at the Scuba Ranch in Terrell, Texas.
Questions have been raised over his behaviour following the incident, as he was out of the water and ‘bone dry’ according to a witness, Richard Thomas, who was teaching an instructor course at the Scuba Ranch the same day.
Dylan’s body was found at a depth of around 13 metres (45ft) by one of Thomas’ colleagues after just 7 minutes of searching.
Serious questions have also been raised over the behaviour of the Kaufman County Sheriff’s Office who were investigating Dylan’s death.
Dylan’s parents reportedly received a phone call just 97 minutes after their daughter was pronounced dead, telling them that the investigation into the incident had already been closed – although the Kaufman County Sheriff’s Office has since told Fox4 News that the case remains open.
Specialist scuba diving attorney David Concannon, representing the Harrison family, has also spoken out against the Kaufmann County Sheriff’s Office’s handling of the investigation, particularly its failure to recover any data from the dive computers that were in use that day.
Armstrong claimed in his police interview that the team were descending one by one down a line when Dylan disappeared, but other students have said they descended as a group, meaning dive computer data would be extremely important in determining which of those scenarios actually happened.
Divemaster Roussel’s computer has reportedly been ‘lost’ in the months following the tragedy.
Armstrong and the dive centre he was working for, Scuba Toys, were both permanently suspended from teaching at the Scuba Ranch in the immediate aftermath of Dylan’s death.
NAUI issued a statement on 27 October but has so far not provided information on the current teaching status of Armstrong and Roussel.
‘We are deeply saddened by the dive training incident that happened on August 16th, 2025,’ said a NAUI representative. ‘Both the dive instructor and dive master present during the incident are NAUI (National Association of Underwater Instructors) sanctioned leaders.
‘As with all of our sanctioned and certified instructors, safety has been and always will be our top priority. Our team will work closely with the appropriate authorities if needed. At this time, we are unable to comment further on this pending investigation.’
