ROME (AP) — Two-time swimming world champion Filippo Magnini and sprint relay teammate Michele Santucci are being questioned by Italian anti-doping authorities over their relationship with a nutritionist being investigated for alleged illegal drugs distribution.

Authorities in Pesaro already cleared Magnini in the case but they allegedly have proof of unusual meetings, phone conversations and payments between the swimmer and Guido Porcellini, the nutritionist.

Magnini, who won the 100-meter freestyle at the 2005 and 2007 world championships, has never tested positive and maintains that he never doped. He has been an outspoken critic of doping throughout his career, having taken part in an "I am doping free" initiative.

Santucci teamed with Magnini when Italy won bronze in the 4x100 relay at the 2015 worlds.

Porcellini has previously been sentenced in two other cases, for cocaine trafficking and for domestic abuse.