The owner of a stolen trailer spotted it for sale on online trading site Gumtree the following day.
The dual carriage trailer was stolen from Bibra Lake some time on Monday, Sgt Gerry Cassidy said.
The owner saw it being offered on Gumtree for $1600 the following day. He arranged to meet the seller and confirmed it was his trailer, then notified police.
Police took a 38-year-old and 34-year-old into custody just before 3.30pm in Wellard yesterday and investigations will continue into other possibly linked incidents.