New York (CNN) -- Two U.S. senators have requested more information from the British and Scottish governments regarding the release of a Libyan man convicted in the 1988 bombing of Pam Am Flight 103, which killed 270 people.
At a Monday news conference at Newark Liberty International Airport, Senators Robert Menendez and Frank Lautenberg outlined the investigative portion of their plan to find more information about the circumstances surrounding the release of bomber Abdelbaset al Megrahi from a Scottish prison nearly one year ago.
They also released the first in a series of letters to the Scottish government requesting new information.
Menendez will chair a Senate hearing on the matter in the coming months, which was originally scheduled for July 29 but was postponed when key witnesses from BP and the Scottish and British governments declined to testify on that date.
He has announced a new plan to gather information, which includes an investigation that his office will spearhead and that will help inform the Foreign Relations Committee's hearing.
The senators plan to review all documents already made public by the British and Scottish governments and all documents newly released to Menendez by the British government.
The senators also hope to interview key individuals including those outside the United States.
In addition to outlining the scope of the investigation, Menendez and Lautenberg also sent a letter requesting answers about the Scottish Parliament and Parliament Justice Committee's inquiry into the release of al Megrahi.
Scottish officials commonly cite the inquiry as having produced comprehensive information on the matter, however the senators said the inquiry focused on the process of releasing al Megrahi instead of the decision, and the list of witnesses interviewed was limited.
"In reviewing the documents available from your inquiry in the absence of direct testimony, it seems that the inquiry was quite limited, which leads me to the first series of questions we would appreciate your help in answering," the senators wrote.
Obama administration officials, last month, took what was described as an "exceptional step" to make clear that they had strongly opposed al Megrahi's release.
A group of senators from New York and New Jersey have repeatedly voiced suspicions that Scottish authorities released al Megrahi as part of a deal allowing oil giant BP to drill off the Libyan coast. BP, a British corporation, is already dealing with a public relations nightmare as the company responsible for the Gulf of Mexico oil disaster.
Menendez has accused the Scottish and British governments of trying to point the finger of blame at each other in the decision to release al Megrahi.
In declining requests for Scottish officials to testify at the July 29 Senate hearing, Scottish First Secretary Alex Salmond wrote that the "Scottish Government would also be happy to answer, formally and in writing, any additional questions that may arise around the hearing."
Menendez and Lautenberg were part of a group of four senators who met with British Prime Minister David Cameron in July, asking the British leader for an independent investigation into the release of al Megrahi and any possible involvement BP might have had.
Most of the bombing victims were Americans. The flight was headed from Frankfurt, Germany, to New York via London, England, when it exploded in the air over the Scottish town of Lockerbie. Among the 270 people killed were 11 people on the ground.
Al Megrahi was convicted in the case and sentenced to life in prison. The Scottish government released him on compassionate grounds in August after doctors said he had terminal prostate cancer and just three months to live. Al Megrahi is still alive, however, and news reports in recent days have questioned whether he was as sick as depicted.
Under the Scotland Act 1998, Scotland has its own government that is responsible for most of the day-to-day issues there, including the justice system.