We, as the recipients of the news and rumors, were lead to believe that Cheema had a ticket to Algiers.
That wasn't how it was stated, however. It was said that a ticket (which morphed into a "one-way ticket" somewhere along the line) to Algeria (the country) had been found which "traced back to Cheema."
Obviously, now we know that the ticket that was found belonged to the Algerian man who was heading back to his country--and that he had been found by the police to be in the same apartment with Fazal Cheema.
That's how it tracked back.
We don't know that it's the same ticket. The one traced to Cheema was said to be for several months in the future, not the day after the bombing.