Dorset Police said in a tweet early on Tuesday morning (July 31): "Regarding tweets to @TomDaley1994 - 17-year-old man arrested this morning at a guest house in the Weymouth area. Enquiries continue."
The force had confirmed last night that it was "aware of the issue and... actively looking into it".
Daley was subjected to abuse on the microblogging site on Monday (July 30), following his fourth place finish in the synchronised diving.
The Olympic sportsman retweeted a message from a particular user, who referred to Daley's late father by commenting: "You let your dad down i hope you know that."
The individual initially apologised and claimed that he didn't know about Daley's father's death, but soon continued to post abusive messages.
He called Daley an "over-hyped pr*ck", a "little p***y" and "an absolute waste of space", adding: "i'm going to find you and i'm going to drown you in the pool you cocky tw*t your a nobody people like you make me sick"
Daley has since told his followers: "Thank you everyone for all your support before, during and after the synchro, the atmosphere was incredible! Now focussing on the individual."
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