Financial crimes investigators interviewed Mathews for several hours Tuesday.
The questioning comes a day after Sri Lanka Cricket, the sport's local governing body, suspended senior bowling coach Anusha Samaranayake for links with a practice bowler who is said to have brought the offers.
Left-arm spinner Rangana Herath and opening batsman Kusal Perera are reported to have made the complaints over the approaches.
Samaranayake has been suspended for two months pending an inquiry.
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