Those who had seen it described what had happened to the demon-possessed man and also to the pigs.

Matthew 4:24
News about Him spread all over Syria, and people brought to Him all who were ill with various diseases, those suffering acute pain, the demon-possessed, those having seizures, and the paralyzed--and He healed them.

Matthew 9:32
As they were leaving, a demon-possessed man who was mute was brought to Jesus.

Mark 5:15
When they came to Jesus, they saw the man who had been possessed by the legion of demons sitting there, clothed and in his right mind; and they were afraid.

Mark 5:18
As He was getting into the boat, the man who had been possessed by the demons begged to go with Him.

And they that saw it told them how it befell to him that was possessed with the devil, and also concerning the swine.