In the first excerpt (on what preceded the yellow house visit), I think I can read out something between the lines:

'The material within [from the office of the court] does not contain specific material from Albania; but a low number of witness statements and other material we have confirms and to a certain extent amplifies the stated information,' I noted in a memo on this activity.

...The victims of these cases were probably seized after the end of the NATO air campaign... It was not clear whether crimes committed in this arc of time fell under the mandate of the tribunal.

The prosecutors office should have asked for the names of the sources from the journalists and UNMIK as well as any other information they had on this case.

E.g., this case didn't solidify further not because of simply weak evidence but because it wasn't properly investigated; Del Ponte suggests her hands were bound, with the territorial and temporal limits to her Tribunal. The last sentence is mysterious, her being the Chief Prosecutor; does she suggest some outside (or lower-ranked inside) powers prevented the prosecutors' office from taking action?

From the second excerpt:

The house was now white. The owner denied it had ever been repainted even though investigators found traces of yellow along the base of its walls.

...The syringes, the iv solution bags, the gauze are clearly material which confirms the tales, but as proof they are unfortunately insufficient. The investigators were not able to determine whether the traces they found were of human blood. The sources did not indicated the position of the grave of the presumed victims and so we did not find the bodies.