Unfitting details about the discovered Abu Salim massive grave

Concerning the recently discovered massive grave of the Abu Salim prison victims, there are some details casting doubts on the incident.

According to Human Rights Watch and the Amnesty International the only existing eyewitnesses of the massacre are two persons: Hussein al-Shafa, who was inmate working as a cooker by that time and disclosed his experience to the organizations 

The other one is an anonymous member of the National Front for the Salvation of Libya (NFSL), an opposition political group based outside Libya.

Shafa stated that after the massacre "Cleanup began around 11:00 a.m. the next day, June 30, when security forces removed the bodies with wheelbarrows. They threw the bodies into trenches—2 to 3 meters deep, one meter wide and about 100 meters long—that had been dug for a new wall. “I was asked by the prison guards to wash the watches that were taken from the bodies of the dead prisoners and were covered in blood,” al-Shafai’i said. In 1999 security officials poured cement over the trench, he claimed, although he believed that they later had the bodies removed."

The NFSL member reported that after the massacre "refrigerator trucks from the Meat Transportation Company and the Marine Fisheries Company took bodies away. On June 30, a forklift loaded the last bodies into a container for trains."

Both descriptions indicate that ether the bodies should be under a (massive) wall, or had been taken away. 

According to the Huffington Post the place of the alleged discovered massive grave was "a desert field scattered with bone fragments" that "was found outside the walls of Tripoli's Abu Salim prison, where the victims were killed on June 26". 

France 24 reports: "A bone wrapped with rope and skull fragments scattered over a cactus-covered desert field are grim testament to a 1996 massacre of more than 1,200 prisoners by Moammar Gadhafi’s regime." 

Daily Mail says "The human remains - found in a desert field outside the notorious Abu Salim Prison in Tripoli - are believed to be those of prisoners massacred by Gaddafi's henchmen in 1996." 

According to the BBC's video the scene is the one of the following picture.

Dr Ibrahim Abu Shima of the NTC stated that the place was discovered after successful interrogations of former prison guards that they all depicted the same place. But the fact is that their confessions contradict both prisoners that accordingly differ in this part of their reports.

Finally, according to the CNN: "It was unclear, however, whether the site actually was a mass grave, as no excavation has taken place. Members of the media were shown bones at the site, but medics with CNN staffers on the scene said the bones did not appear to be human".

Deciding on the issue is premature but could it be a symbolic firework aiming to unify the rather fragmented rebels council offering at the same time a hard-proof justifying the rebellion that started from the relatives of the Abu Salim victims along their lawyers?