Detlev Mehlis, the UN investigator in charge of the probe into the murder of Rafiq Al-Hariri says he's turned a corner. A few days ago he criticised Syria for their lack of co-operation. Bashar Al-Assad immediately replied by offering full support to the inquiry.

Mehlis said today that, "there were some problems but I'm optimistic that these problems can be solved." He says he's willing to take up the invitation to Syria.

It also appears that the five suspects arrested by Lebanese authorities had been central to the Mehils investigation. They were "extensively interviewed" by the UN, but he insisted that they were innocent until proven guilty.

So was that the reason for the arrests this week? Guilt by association?

The Lebanese investigators were fiercly condemned by the UN for their Hariri investigation. It was labelled incompetent at best, and criminal at worst.