know somebody's identity

He did not even know the identity of his parents.

He knew everyone should know her true identity by now.

Now she knew their identity, and what had happened to them.

He was the only person who knew the boy's identity.

He is probably the only one who knows her true identity.

He knew the identity of the man who walked by.

Soon he would know the identity of that person, and take him out.

Perhaps we'll never know the identity of her baby's father.

The police did not know the man's identity, officials said.

Even if it was given before she knew his identity.