A visitor

Last night I was visited by a ghost.
"I'm lost." He was just a shadow at the foot of the bed. I could not see his face.
"Who are you?" I asked, but I knew the answer. I knew who he was.
"I'm not anybody," he said. "Not now."
"What do you want?"
"I want to be somebody again."
"Do you want to be me?"
"Are you me?"
This was strange, talking to a shadow. I am locked away in an asylum and I am mad. The shadow was not quite a shape. The voice was an echo in my skull. Whose voice?
"I used to live here," said the ghost. "I escaped."
I wanted to explain to him. What I was doing here, in his cell. Why I was calling myself...
"They put me here." I said. "They think I'm you."
"Who do they think you are?" the ghost wanted to know. Was there desperation there?
Thomas Grimes.
"They think I'm him. Jack The Ripper."
"It that what happens to me?" the ghost asked. "Do I become you? Do I become a monster?"
"I'm not a monster," I said.
"You look like one," said the ghost. "That's enough for most people."