Judgment_paragraph 97 · HF v European Parliament (T-218/17)

97As regards the fact that the Advisory Committee did not hear all the persons whom the applicant wished to see testify, the Court notes that the entity responsible for an administrative investigation, which is required to investigate the files that are submitted to it in a proportionate manner, has broad discretion with regard to the conduct of the investigation and in particular with regard to assessing the quality and usefulness of the cooperation provided by the witnesses (judgment of 11 July 2013, Tzirani v Commission, F‑46/11, EU:F:2013:115, paragraph 124 and the case-law cited).