Surveillance video that investigators believe captured the handoff of an explosive-wired laptop that blew a hole in the side of a Somali jetliner could prove the bombing was an inside job, sources told Fox News.

The explosion on board Daallo Airlines Airbus A321 at 11,000 feet Tuesday killed the suspected bomber, who was sucked out of the plane, and forced an emergency landing.

A source close to the investigation showed Fox News the security video from Mogadishu’s airport, which shows two men, one an airport worker in an official reflective vest, passing the laptop to the bombing suspect in the airport terminal after he passed through a security checkpoint and shortly before he boarded.

The source said investigators, including several from the FBI brought in at the Somali government’s invitation, believe they have identified that all three men. They are believed to be from Hargeisa, in the disaffected area of Somaliland, which has been contesting sovereignty with the Somali government. That is a departure from initial suspicions that the bombing was carried out by the Al Qaeda-linked Islamist terror group Al Shabaab.

In the security video, an airport worker in a branded vest and a man casually dressed in white shirt and trousers, are first seen walking from the top to the bottom of the picture, along a walkway to the side of one of the airport’s open departure lounges. The man in the white shirt can be seen carrying a small laptop. Passengers can be seen waiting for their flights. This whole area is known as ‘airside’ – accessible only to passengers and airport staff who have gone through comprehensive security checks, including X-ray machines.

Security in Mogadishu’s airport is tight. In conjunction with Somalia’s National Security Agency, it is run by Turkish officials, as a Turkish aviation company manages the airport. It’s believed security staff are trained and constantly advised by both UN and U.S. specialists.

Moments later on the video, a lone person who investigators believe is the man who carried the laptop on board, and later fell to his death can be seen walking slowly toward the camera along the walkway. The man in the white shirt and the man in the airport vest come back into the picture from the bottom of the frame, stop the passenger, and hand him the laptop. All three men move off within seconds, the man in the security vest talking on a cellphone.

Fox News has learned several airport officials have been arrested in connection with the blast.