Here's an excerpt from Sam Wasson's “The Big Goodbye: Chinatown and the Last Years of Hollywood.” The scene takes place late summer, 1969, Los Angeles, after the Manson killings. The killers haven't been caught, or even IDed, people are freaking, Robert Towne and his wife Julie Payne live nearby. Julie wants a gun, Towne looks into security, and they consult former cop Tony Silas:

In due time, Tony Silas paid a visit to Hutton Drive and instantly understood why Payne wanted that gun. Their house, up on a hill at the end of a curled driveway, was like the house atop Cielo Drive, distressingly isolated. Should anything happen, there would be no escaping. “Get her the gun,” Silas told Towne. “If anybody came up this driveway,” Silas continued, “forget it. Women shoot to kill.”

Towne got the message. “Where do you work?” he asked the vice cop. “Right now we're working in Chinatown.” “What do you do there?” “Nothing.” “What do you mean, nothing?” “Well, that's pretty much what we're told to do in Chinatown, is nothing. Because with the different tongs, the language and everything else, we can't tell whether we're helping somebody commit a crime or prevent one. So, we just ... we do nothing.”

As little as possible. It's right there. And the circularilty of it is mind-bending. Because of security moves in the aftermath of the Manson killings, Towne gets the germ of what would become “Chinatown” ... which will be directed by the man whose wife and unborn child were killed by the Mansons. It's all taking place in Hollywood, but if this was in a Hollywood movie I wouldn't believe it.