A senior police officer said there was foul play found in the incident, which occurred on April 27.
Delhi Chief Minister Arvind Kejriwal met the family members of the girl, a Class 9 student of a government school.
Police was also probing whether the girl committed suicide and are speaking to her friends and teachers to ascertain whether she was depressed.
Police registered a case under Section 338 (causing grievous hurt by act endangering life or personal safety of others, punishable with a maximum term of two years and fine) on April 30 in the matter and are probing whether there was any negligence on the part of the school authorities that led to the girl's death
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