Letter to dignitary

[Unregistered]

I'm writing a formal letter to a dignitary and need help addressing it. I know that the dignitary's title must be included in the address line but how about the directive portion of the letter? Example:

Mayor Ray Nagin
Address XXXX
City, Stater Zip

Dear Mayor Ray Nagin,

or should it be

Mayor Ray Nagin
Address XXXX
City, Stater Zip

Dear Mr Ray Nagin,

[Anglika]

I'm writing a formal letter to a dignitary and need help addressing it. I know that the dignitary's title must be included in the address line but how about the directive portion of the letter? Example:

Mayor Ray Nagin
Address XXXX
City, Stater Zip

Dear Mayor Ray Nagin, Dear Mr Nagin OR Dear Mayor

or should it be

Mayor Ray Nagin
Address XXXX
City, Stater Zip

Dear Mr Ray Nagin,

..