The bodies of two girls were on Sunday found on railway tracks in Tughlakabad in southeast Delhi, police said.
The incident came to light around 6 pm. The girls were hit by a train, following which they were rushed to a hospital where they were declared dead, they said.
The police team found a bag which had a note saying "sorry father" written on it.
Police claimed to have learned that one of the girls' mother had died a few years ago and she was depressed.
They suspect it to be a case of suicide, but they are probing the case from all the angles, police said.
Police are also probing whether they were students of Class 12 and were depressed because of the CBSE results.