This happened on April 22 in the presidential palace of the capital, Brasilia.
The BBC has lost a security guard in the palace due to not agreeing to rescue the dog.
There are two dogs named Pikoli and Thor in the family of Brazil's president Michel Tim.
On the day of the incident, Marshall was walking in the garden with Sinha, Marshalla was walking in the garden. Suddenly, he saw Piccolo drowning in the lake.
He did not waste the time to save Pikoli. He jumped into the lake and drove the dog down.
But the United Kingdom's charitable organization RSPCA, working for the welfare of animals, believes that people should not be threatened by threatening animals to save animals from water.