Overnight, armed police patrolled parts of the city's suburbs as detectives released a picture of a suspect.
Dale Cregan, 29, is wanted for questioning after the man's body was found yesterday.
Officers were called to Folkestone Road East in the Clayton area at around 10.30am following reports of gunfire and discovered the victim. They believe an explosion had also occurred at the scene.
Nine minutes later, officers received reports of gunshots at a house on Luke Road, Droylsden, where a second explosion is believed to have taken place. No one was injured during the incident.
Cregan, from the Droylsden area, is already wanted in connection with the murder of Mark Short at the Cotton Tree Pub on May 25.
Assistant Chief Constable Garry Shewan, said: "Things have moved on apace since this morning but we still don't know with any certainty what happened or why.
"We do believe both incidents are linked and are looking at the very real possibility that they are connected to the recent fatal shooting of a young man at a pub in Droylsden.
"We have issued a picture of Dale Cregan and I would urge anyone who knows of his whereabouts to come forward. If you see him, do not approach him but call police immediately.
"Extra officers, including specialist firearms officers, are in both areas and we will have a significant police presence over the coming days and I would urge anyone with any concerns or who has any information they may want to share to come and speak to us."
A post-mortem examination will take place to establish exactly how the man in Clayton died.
Anyone with any information is asked to call police on 0161 856 3301, or Crimestoppers, anonymously, on 0800 555 111.