"There have been 18 deaths in Tihar jail in 2012 out of which 16 were natural while two were cases of suicide," said Vimla Mehra, director general (prisons), addressing a press conference recently.
A senior jail official said Singh's suicide is the first such incident this year while another inmate had died due to natural causes.
He said magisterial inquiries are conducted into every death that takes place inside the jail premises.
Considered India's largest and most secure prison, Tihar has a three-layered security system.
Surveillance and external security is with the personnel of ITBP and CRPF followed by Tamil Nadu Special Police which man various gates and frisk visitors.
Jail operations are taken care of by personnel of Delhi Prisons.