The Economic Offences Wing of Delhi Police's Crime Branch registered a case under Section 66 of IT Act, which deals with punishment for sending offensive messages through communication services, on September 29.
The registration of the case came after after 44-days of investigations into a complaint filed by Singh's lawyer Rohit Kochar on August 16 during which police prima facie found a case against those 22 people, a senior police official said.
Singh sought police action for causing "severe damage to his goodwill and reputation besides inflicting acute mental pain and agony on "him, his family, friends and colleagues".
"The same is also causing grave damage and injury to the reputation, goodwill and image of the Congress party to which Singh is the General Secretary," the complaint said.
Singh had sought registration of a case against 22 people and eight websites alleging that they have committed serious criminal offences against him by using computers to send and post "highly offensive, menacing, annoying, insulting and injurious content, messages, pictures and other data".
64-year-old Singh has courted controversy at regular intervals with remarks on Hindutva terror, Batla House encounter, Maoism and Home Minister P Chidambaram.
In his complaint, Singh alleged that several known and unknown persons have been posting hatemails, pictures and other "disparaging and defamatory" content against him which is "grossly offensive, menacing in character and is designed to cause annoyance, insult and injury to his reputation. The complaint urged the police to take "urgent and necessary action" against those responsible for posting such comments which caused "severe damage to his goodwill and reputation besides inflicting acute mental pain and agony on "him, his family, friends and colleagues".
Singh had named the websites Facebook, Orkut, Ibibo, Twitter, MSN, Youtube, newsofdelhi.com, dhimagkharab.com in his complaint and sought registration of a case against then under Section 79 of IT Act but police has not done so.
In the complaint, Singh had argued that statutory obligations imposed upon websites and social networking platforms do not allow them to absolve themselves of the obligation to perform their duties and responsibilities.
The complaint noted that some of these comments were posted by people who have identified themselves but others are posted as anonymous.