A constable of Sikkim Police shot dead five of his colleagues and injured another after an altercation in Daryaganj area of old Delhi early on Sunday. He has been arrested.
Constable JV Subba shot dead his colleagues at around 5 am with his short-range rifle and also attacked them with a sharp-edged weapon at the Dena Bank branch near Golcha cinema, Daryaganj, where they were posted on guard duty, police said.
Police have ruled out robbery as a motive behind the crime.
The injured, constable Nari Lapcha, was taken to the Lok Nayak Jai Prakash Narayan hospital nearby where doctors said he was out of danger and recovering.
Lapcha told police that Subba opened fire over some misunderstanding. Police arrested Subba and are interrogating him.
"The matter is being investigated," said Akshay Sachdev, an official of Sikkim Police.
The dead have been identified as Lance Naik Vishal Tiwari, Constable Karma Bhutia, Constable Shanti Veer, Lance Naik Kumar Basant and Constable Lakshman Subba.
Sikkim Police have around 350-400 personnel posted in Delhi. They guard banks and embassies in the capital.