Constable's wife Raj and her lover Mukesh have been arrested and the two have confessed to their involvement in the crime, SSP Nitin Tiwari said.
According to initial reports, Ajit, who died of bullet wounds, had committed suicide after a tiff with wife but his family had alleged that he was murdered, Tiwari said, adding the suicide story was woven by Raj to misguide the police.
Ajit was attached with the Shakarpur Police Station in Delhi and was staying in the Rajendra Nagar area.
When Raj was quizzed on the basis of child's revelation, she disclosed to have given the pistol to Mukesh, who killed Ajit, Tiwari said.
He further said according to post-mortem report, there were four bullet wounds in the victim's body, which is practically not possible if a man commits suicide.