Question

what was the intruder trying to gain by taking Gerard place​

Answer 1

Answer:

The Intruder was a criminal. He had murder and he did not wanted to hang. Intruder was being wanted by the police so he hatched the very smart idea of impersonating him as a gentleman who was not under the police scanner.

Answer 2

Answer:

The Intruder thought if he killed Gerrard and took on his identity, he would not get caught. He would gain his freedom and would be free to go places. He could live without the fear of cops.