The Việt Nam International School's swimming pool where a male 9th-grade student drowned on Tuesday. — Photo courtesy of the school

Trần Lâm Thắng, 24, is being investigated over "lack of responsibility, causing serious consequences" following the death of the boy.

On the Tuesday afternoon, the ninth graders of A1 class had a swimming lesson from 1:20pm to 2pm, supervised by Thắng.

Thắng gathered 27 students from the A1 class in the pool area to prepare for the lesson.

The class was divided into two groups after warming up for 10 minutes.

One group engaged in sports activities in the schoolyard, while the other group, comprising 11 students including the 15-year-old student named P.H.A., was led to the pool for swimming practice.

It has been alleged the teacher did not provide any guidance and sat in the front seat of the pool, letting the students swim freely and practise on their own.

It is also claimed Thắng did not supervise the students and frequently used his mobile phone. 

Thắng failed to notice that student P.H.A entered the pool but did not swim. The boy only went into the pool to a depth of 1.2m and 1.55m before being unable to walk further. 

This student struggled continuously for about three minutes before sinking.

At that time, it is alleged Thắng remained at his previous position using his mobile phone. 

About 20 minutes later, he asked the students to get out of the pool. No one had discovered the drowning of student P.H.A.

At 2:06pm, the cleaning staff Hà Văn Xuân discovered P.H.A lying motionless at the bottom of the pool at a depth of 1.55m while he was cleaning the pool.

Xuân and some other teachers rushed the student to Hà Đông General Hospital for emergency treatment. 

However, the boy had died before arriving at the hospital. — VNS