While a fellow prisoner has alleged that the victim was tortured to death, police ruled out the charges, saying he committed suicide.
Victim Vineet Sharma, brother-in-law of the slain constable, was arrested by Indirapuram Police along with one more person Narendra.
SSP Nitin Tiwari ruled out allegations of custodial death, saying that Vineet committed suicide and the post-mortem report will bring out the truth.
Stressing that a thorough inquiry will be conducted into the matter, Tiwari said no departmental official will be spared if found guilty.
Narendra, however, has alleged that they were given third degree torture and Vineet died of electric shocks.
Constable Suresh Kumar Sharma and his wife Babli were found dead in the CISF staff quarters on April 24.