Some experts said senators' calls for an investigation present an opportunity for both Democrats and the GOP to gain voters' approval by publicly flogging BP, the company responsible for the largest oil spill in U.S. history.

What's more, Senators can also cash in by portraying themselves as tough on terrorism, some experts said.

"This is a win-win situation for Democrats and Republicans," said Marko Papic, senior Eurasia analyst at global intelligence company Stratfor.

"BP is an easy target. The fact that this is being resurfaced is just political theater," he said.

The issue comes at a time when Americans are viewing Congressional incumbents - mostly Democrats but also some Republicans - as out of tune with voters' needs in the worst economy since the 1930s.

Some are also viewing the Congress and the White House as trying to spend their way out of a recession - which is not helping diminish double-digit unemployment numbers, critics stress - amid much drumbeating over the ballooning deficit.

Still, families of those killed in the bombing were outraged when it was reported earlier this month that al-Megrahi could survive perhaps another decade.

The convicted bomber is now back home in Libya where he is hailed as a hero, and some victims' family members are calling for a Congressional hearing to question BP executives on the matter.

The issue overshadowed British Prime Minister David Cameron's visit to Washington earlier this month, although he had previously expressed his opposition to the bomber's release.

Senate Foreign Relations Committee members expressed irritation that BP executives did not show up for Thursday's hearings. New Jersey Democrat Robert Menendez on Thursday told the BBC that he wanted to see the investigation include interviews with officials including former British Justice Secretary Jack Straw.