While Sírithon sends news of the theft to Felegoth and awaits assistance, there is much else to be done in Loeglond.
'I will send word to Felegoth. Truly, I know not whether aid will come. As of late, what with the closures in trade and whisperings among the rafts of this and that - yet I will not stoop to gossip.
'I must send word and wait. While I do, perhaps you might continue assisting Lorndúr?'
You should assist the Raft-elves of Loeglond.
The Trail of Rust quest arc will continue after completing the Reopening the Realm quest arc which begins with Thranduil in Felegoth.
You should travel to Esgaroth-of-old, which is located east of Loeglond.
The voices were coming from somewhere in the ruins of Esgaroth-of-old, upon the Long Lake.
You should investigate the voices, listening when you can and defeating any foes to protect yourself and keep the way safe.
You should talk to Thorlind, who can be found just outside of Esgaroth-of-old.