Eight dogs that died after being walked along a popular North Yorkshire footpath may have been deliberately poisoned, the RSPCA has said.
The dogs had seizures and died after being walked on a path off Station Road in Cross Hills near Keighley between 20 May and 25 May.
Anyone with information has been asked to contact North Yorkshire Police or the RSPCA.
The footpath has been cordoned off while tests are carried out.
Blue-green algae in a nearby lake has been ruled out as a cause following Environment Agency tests.
Sally Ramsden, RSPCA animal welfare officer, said: "We don't know what could be causing this but we strongly suspect that the dogs may have been poisoned.
"We also cannot rule out the possibility that this is being done deliberately.
"These dogs have suffered horrendously and we desperately need to hear from anyone who has information about these incidents."