Abdel-Jalil, who stepped down as justice minister to protest the clampdown on anti-government demonstrations, didn't describe the proof.
Gaddafi has accepted Libya's responsibility for the bombing of Pan Am Flight 103 over Lockerbie, Scotland, which killed all 259 people on board and 11 on the ground, and paid compensation to the victims' families.
But he hasn't admitted personally giving the order for the attack.
Abdel-Jalil told Expressen that Gaddafi gave the order to Abdel Baset al-Megrahi, the only man convicted in the bombing.
Al-Megrahi was granted a compassionate release from a Scottish prison in August 2009 on the grounds that he was suffering from prostate cancer and would die soon.
He is still alive.
Most of the victims in the Lockerbie bombing were Americans, and al-Megrahi's release has been criticised by members of the US Congress and the victims' families.
Although he didn't directly comment on Mustafa Abdel-Jalil's Lockerbie allegations, Wednesday evening saw US President Barrack Obama speak openly against Gaddafi for the first time since the protests in Libya began over a week ago.
He condemned the violence in Libya as "outrageous and unacceptable" and said he was dispatching US Secretary of State Hillary Clinton to Geneva, Switzerland next week for international talks aimed at stopping the violence.
"The American people extend our deepest condolences to the families and loved ones of all who have been killed and injured," Obama said in brief remarks at the White House.
"We strongly condemn the use of violence in Libya," Obama said. "The suffering and bloodshed is outrageous, and it is unacceptable. So are threats and orders to shoot peaceful protesters and further punish the people of Libya."
Obama said that he was looking at options including possible sanctions that the US could take with its allies as well as steps it might take alone to pressure Moammar Gaddafi's regime to halt attacks against anti-government protestors in Libya.