It is feared lives could be put at risk after water safety equipment was vandalised in two different Dundee locations at the weekend.
Life rings and poles were removed from their positions at Broughty Ferry beach, near Broughty Castle, and thrown in the water.
Rings at Clatto Country Park were also vandalised and thrown in the water, with one set on fire.
Equipment advertised on Gumtree
It comes after crucial lifesaving equipment from the Tay Bridge appeared for sale on Gumtree for £20.
The life-ring, marked with a code for its position at the bridge, was found washed up on the beach at Carnoustie earlier this month and put up for sale.
Coastwatch Tay, the group which looks after all coastal life-saving equipment for Dundee City Council, revealed the find after the weekend of vandalism.
In the warmest weekend of the year so far, graffiti has been daubed on walls of the historic barracks at the castle.
The actions have angered local community leaders as well as the people who volunteer for Coastwatch Tay.
William Brown, depute station officer for the group, said destruction and removal of safety equipment along the banks of the Tay is becoming more common.
Mr Brown said: “This is something we are seeing more and more of unfortunately.
“Only around three or four weeks ago a member of the public phoned us to say that one of the city’s life-rings was for sale on Gumtree.
“This turned out to be one from the Tay Bridge. We contacted the vendor and pointed out the error of his ways.
“On this occasion the ring was returned to us.”
Mr Brown also said damaged life-rings at Clatto and Broughty Ferry had only been installed on Thursday.
He added: “Rings at Broughty Ferry pier were removed and thrown away.
“These were recovered and put back in place.
“Rescue reach poles however, that were also removed, are still missing.”
Life-rings have now been put in cases in a bid to stop the vandalism.
Mr Brown said the group is trying to educate people about the dangers of tampering with safety equipment.
He said: “We have spoken to people and asked them what they would do if one of their loved ones needed this equipment and it had been vandalised or thrown away.”
‘Could cost a life’
Broughty Ferry councillor Craig Duncan called the vandalism “unacceptable”.
“The removal of this crucial equipment could cost a life,” he added.
“It’s so disappointing to see this type of behaviour return on what was the first really nice weekend of the season.
“I dread to think that this is only the start of this kind of behaviour.”
He added: “We need to nip this in the bud now before it gets any worse and the unthinkable happens and someone dies as a result of life-saving equipment being vandalised or not even there at all.
“The graffiti on the walls beside the castle is also completely unacceptable and the cost comes back to all tax payers for this to be removed.”
Dorothy McHugh, chairwoman of the Friends of Clatto group, said: “Vandalism of life belts has, unfortunately, been a regular feature at Clatto since the lifebelt stations were moved to the top of the embankment around a year ago.
“The water level was so high at the reservoir, that the original lifebelt stations were standing in feet of water.”
She added: “Once the stations were positioned just off the pathway around the reservoir, they became much more accessible – with the result that it was a regular occurrence for them to be thrown into the reservoir, set alight, etcetera.”
A Police Scotland spokeswoman confirmed enquiries into the vandalism are ongoing.