Peter told them that Jesus healed the man and only Jesus could save people.

Acts 4:8-12

8 So as the Holy Spirit completely controlled Peter, he said to them, “You fellow Israelites who rule us and all of you other elders, listen! 9 Today you are questioning us concerning our doing something good for a man who was crippled, and you asked us how he was healed. 10 So we(exc) want you and all of our other fellow Israelites to know this: It is because Jesus the Messiah [MTY] from Nazareth healed this man that he is able to stand here. God considers that it was you who nailed Jesus to a cross, but God caused him to become alive again. 11 In the Psalms this was written about the Messiah:

He is like [MET] the stone that was rejected by the builders {that the builders rejected}.

But that stone became the most important stone in the building that they were building.

Jesus is that stone, and you are those builders who threw away the stone that was the most important one. 12 So he alone can save us [MTY]. God has sent only one person [MTY] into the world who can save us from the guilt of our sins, and that person is Jesus!”