Teenage girl and a boy jumps to death from the 67th floor of an apartment complex

Two teenagers aged 15 studying in an International school in Colombo 07 have died by jumping off the 67th floor of a luxury apartment complex in Slave Island.
Slave Island Police must inspect the security of the apartment complex. If the apartment complex is so big they should provide good security. If they Provide good security to this apartment how those two went up?
The deceased have been identified as male and female students residing in Kelaniya and Wellawatte