He is now battling for his life at a hospital in the national capital.
He suffered brain hemorrhage when the police used force to overpower him to end his killing spree.
On the ill-fated night, the accused, 49-year-old Naresh Dhankar, had reportedly gone to meet his estranged wife at the residence of his in-laws.
Sources said Naresh even wanted to meet his son, for whom he had got fruits from the market.
The former lieutenant was denied entry into the house while his wife refused to meet him.
A frenzied Naresh lost his mind, picked up an iron rod from a nearby location and went on a killing spree.
He first targeted a pregnant woman at a civil hospital ward leaving her in a pool of blood. He stopped after killing six.
All bodies were found within 150 metre span.
His family members say he was under severe depression because of his estranged relationships.
A year ago, he had stopped taking medicines prescribed by his psychiatrist to keep his frequent bouts of aggression under control. This compounded his ailment.
Before he was declared medically unfit to serve in the military, Naresh had an unsavoury instance where he beat up a soldier of his regiment. He also beat up a police officer.
His older brother, Chanderpal, said Naresh had taken up boxing to divert his bouts of aggression.
The police are yet to record the statement of the accused as he remains critical.
The accused had no connection or hostility with any of his victims, which also included night watchmen and a beggar.
Naresh is a native of Faridabad in the national capital region.
After his short stint in the army, the accused has been working as a sub-divisional officer with the state agriculture department.