"Police" usually refers to a body of people, so the term is usually plural. "Were" is correct, e.g. "The police were present at the scene of the crime."
write a letter to police station for the lost of passbook?
The police station is down the street.
No.
When you write an email to them...
Assuming you're talking about grammar, no, it's "the police have a duty."
to the police
They normally will write you a warning ticket.
He was with a Police who was on his side
Write a letter to the police department in Halifax, Nova Scotia.
Expressed as a decimal fraction, 5/10 is equal to 0.5.
No, but they can write "refused to sign" if they like.
Yes.