"Handling codes” used by Europol (like other police forces) raise interesting questions.

How are sources under C and D codes handled?

What if sources under C and D are combined with “reliability” under no 4?

Evaluation codes (assessment of the source and of the information)

1. The source of the information shall be indicated as far as possible on the basis of the following criteria:

(A) Where there is no doubt of the authenticity, trustworthiness and competence of the source, or if the information is supplied by a source who, in the past, has proved to be reliable in all instances;
(B) Source from whom information received has in most instances proved to be reliable;
(C) Source from whom information received has in most instances proved to be unreliable;
(D) The reliability of the source cannot be assessed.

2. The reliability of the information shall be indicated as far as possible on the basis of the following criteria:

(1) Information whose accuracy is not in doubt;
(2) Information known personally to the source but not known personally to the official passing it on;
(3) Information not known personally to the source but corroborated by other information already recorded;
(4) Information which is not known personally to the source and cannot be corroborated.