Assistant police inspector B P Bhoir of Virar police station said the victim was a 19 years old girl, identified as Urmila Kothi.
Nobody has been arrested in the case yet.
According to the police, the accused informed the girl's mother, by way of prank, that she had eloped with a boy (which was not true).
The victim's mother asked her daughter about the message when she returned home. The girl, who felt defamed and humiliated, killed herself on the night of June 1 by consuming pesticide.