Al-Qaeda targets US natural gas tankers?

About a month ago I rasied this question here. That post contained a link to this story.

In the hours after the Sept. 11 attacks, Richard Clarke, then America's top counterterrorism official, rushed to get the US Coast Guard to close Boston Harbor. His main fear: Al Qaeda might attack a huge liquid natural gas tanker as it glided past downtown buildings.

Mr. Clarke professes to know what few did: that Al Qaeda had used LNG tankers to smuggle agents into Boston from Algeria. He also knew that each ship held as much energy as a nuclear weapon. "Had one of the giant tankers blown up..., it would have wiped out downtown Boston," Clarke said in his book "Against All Enemies."

It seems the story is still alive.

From Boston.com

The Department of Homeland Security is investigating whether Islamic extremists infiltrated the nation by stowing away on Algerian liquefied natural gas tankers that docked in the Port of Boston and has concluded several stowaways may have had links to indicted Al Qaeda terrorists, officials disclosed yesterday.