Thousands of people protested in the eastern Spanish city of Valencia on Saturday, a year after floods killed 229 people.
Protesters were demanding the resignation of regional leader Carlos Mazzone over his handling of the disaster.
They displayed banners with messages such as “Mazon to jail” and chanted, “They did not die, they were murdered.”
With a total of 229 deaths, it was Europe’s worst flood-related disaster since 1967.
Spain’s deadliest flood in modern history
The Mazzone administration has been heavily criticized for issuing the alert too late.
The warning came more than 12 hours after the national weather agency issued the highest warning level for torrential rain.
Residents told Spanish media that by the time they received the message the dirty water was already engulfing their cars, flooding streets and entering their homes.
Under Spain’s decentralized system, the management of disasters falls under the authority of regional governments.
However, Mazzone claimed that his administration lacked the information needed to issue a warning sooner and said that the magnitude was unexpected.
A judicial inquiry into the emergency response is ongoing.
On the day of the flood, Mazzone had an hour-long lunch with a local journalist who had been summoned by the court on Thursday.
Edited by: Wesley Dockery