Local police are hunting some vandals who threw street art into the estuary during the Stretch Arts Festival in Mandurah over the weekend.
One piece of artwork, which was part of the Drift Installation Art Award, was found by event staff in the water on Saturday morning.
They believe it was deliberately thrown into the estuary on Friday night, while a second piece of artwork was also damaged.
Police say the item was retrieved but was "in a bit of a state".
On Saturday night another art piece worth $19,500 was damaged.
According to police, two teenagers were seen running away from the scene by security.
One male is described as in his teens, with fair skin, about 177cm tall, with blonde hair and was wearing blue shorts and a white t-shirt.
The second male is described as in his teens, with fair skin, 167cm tall with a slim build and was wearing a black t-shirt and black pants.
Anyone with information is asked to contact Mandurah Police on 9581 0222 or Crime Stoppers on 1800 333 000.
Unfortunately some uncreative people took it upon themselves to roll some of the street art into the marina overnight. Know anything? 131444 https://t.co/bXrdRr955t
— Mandurah Police (@MandurahPol) May 6, 2017
Long-term Pinjarra resident gifts Shire heritage railway carriages, brake vans
Extent of damage to Bar Therapy following devastating fire revealed
MARC pool reopening date announced after three year closure
Yunderup Island blaze under control
Mandurah's Bar Therapy damaged by fire
Postman injured in Wannanup crash
Man charged after allegedly stealing service medals from Greenfields storage unit
South West resort receptionist charged with 32 fraud offences
Daughter of Port Kennedy hit-and-run victim pleads for offenders to hand themselves in