Give the correct verb form for each of the following. Use the active or passive form as required?

Give the correct verb form for each of the following. Use the active or passive form as required:

1. The man (detain) by the police. He is believed to be a bank robber.

2. No one knows where he (hide). Some people say that he has gone to Taiwan.

3. Listen! There (be) someone at the door.