My dad was murdered on August 30th 1967?
The police complaint report is open records. You need only write a letter titled "Open Records Request". Address it to the Chief of Police of the Department that handled the murder. They have 30 days to respond. You will only get a copy of the initial report, but not the entire investigation. I sense that it is unsolved, so you may be able to contact the Homicide Division and make arrangements to go over the case with someone. Murder cases, if unsolved, are never closed. It is in a cold case file somewhere. If the case was solved and people tried for the murder, then an entire copy of the case would be where able such records are stored. In many states it is the District Clerks Office. Good Luck in you quest.