In journalism school you learn to identify the best source of information for a story and approach that source directly.

Screenwriting sometimes requires the same kind of research. So, for instance, if you need help on a script called “Right of Way” that deals with building a subway line through the heart of Los Angeles, you go to a guy who secures public rights of way for a living.

Better yet, if the guy is also a movie buff with an affinity for noir classics, you get him to write the scene himself.

Paul Smolarski, who contributed this week’s pages, is that guy.

“The Bureau of Engineering, Public Works, the mayor’s office, DWP -- I deal with these people on a daily basis,” said Paul, project manager for a company that designs and installs wireless sites around Los Angeles.

“You get to kind of understand the process of the city operating that people don’t ever see or care about. It’s a comfortable arena for me.”

So comfortable that Paul, a first-time writer, has actually deciphered the meaning of Mayor Napolitano’s secret methane map, the coveted, hand-drawn document that sparked Celeste’s kidnapping. He only hints at the map’s significance in these pages; you can’t give everything away at once, after all. But he has an excellent theory about the map’s value which I will share here tomorrow in the hope that another writer will build upon it.

Perhaps Paul’s greatest achievement was to seamlessly blend his scene’s wonky, public works details into a gripping sequence involving a daring physical stunt, a startling new lead, the fleshing out of several important characters (including Celeste’s daughter Rachel, who’s not even there), and a call to action by Mayor Napolitano.

For now, things are coalescing around the scheduled meeting under the Santa Monica Pier with Celeste’s abductor, a confrontation that Paul has cannily dumped into the lap of our next contributor.

But we do know that Napolitano has subverted LAPD policy with varying degrees of cooperation from Detectives Deland and Gallardo, who will be backing him up at a distance as he hurries toward that midnight rendezvous. Meanwhile, Napolitano’s chief aide Sam Higamatsu, has the AWOL mayor’s back with the press and the city.

Every week, with the help of writers like Paul, Napolitano digs himself in deeper. How long until he gets burned? There's no source material for that one. You'll have to come up with it yourselves.