A Delhi Police head constable was assaulted by over six men outside his house in Rohini area.
The attack took place last night and four persons were arrested today, police said.
Mohan Lal, who is posted with the Crime Branch of Delhi Police, was returning home in Sector 18 of Rohini from office when some persons suddenly started hitting him with sticks.
"Seeing this, a security guard tried to intervene but he was also attacked. After beating the duo, the accused fled from the spot," said a senior police officer.
The whole incident was captured on the CCTV cameras installed outside the apartment, he said.
The officer said that some of the accused returned at around 3 AM in the wee hours today and locals nabbed three of them.
"A case under appropriate sections has been registered at Samai Pur Badli police station. Further probe is on," he said.