Q. What is it supposed to be on the show? A. A residential home. Q. Where is it supposed to be on the show? A.  In Tampa, Florida. Q. When did we see it on the show? A. We see this house twice in Episode 8, of Season 1. The first time is when Harry and LaGuerta, on a road trip to Tampa, go to the house because the stolen car they found at a previous crime site was registered to the home's owner, a psychiatrist named Paul Petrie. But once there, they find the home's front door is sealed with a Tampa police sticker declaring it a crime scene. The second time we see it is in the background when Harry is talking to Dexter on his car phone, while Dex is on a pay phone outside a market. When he hangs up, Harry walks across the street to the Spanish-style home, where he meets up with two Tampa detectives (Raymond & Bean).

They break the police seal on the door and let Harry & LaGuerta into the house.

Harry tells them that Petrie is a possible suspect in a Miami homicide case, but when they learn that the murder took place a week ago, they say that Petrie couldn't have done it, because police found his dead body three weeks ago.

Inside, they find the houses spattered with blood from the murder, and they learn that the victim was savagely beaten to death with a fireplace poker.

They learn that Paul Petrie was a psychiatrist who specialized in adolescent behavior disorder, and who ran his business out of this home office.      
Harry finds an appointment calendar, but the last few pages have been torn out, apparently by the killer, who may be one of the doctor's patients.

Detective Raymond says they have 300 potential suspects (former patients of Petrie), with records at the station going back 22 years, if Harry wants to look at them.

Q. Where can I find it in real life?

Q. How the heck did you figure out where it was?

A.  This one was very difficult.

I had been unsuccessfully looking for this house for months, without any luck. There was no street number visible on the house or the curb, and no street signs visible in the background. The production had even added a fake house number next to the door.
 
So I was focusing my search on the San Fernando Valley and Long Beach, since that's where they filmed almost all of the “Original Sin” scenes.  But this house turned out to be near Century City, on the West Side.
 
As far as I can remember, this is the first time “Dexter” has ever filmed in that in in neighborhood, so I hadn’t even considered looking there.

I had previously done a number of Google image searches, but that also failed to turn up a match.

So I might never have found it except that when I was doing the page about the pay phone market, I noticed that in the scene  where Harry is talking on the phone to Dexter, just after he hangs up, there is a particularly good view of the Petrie house in the background.

So, in a last ditch effort, I took a screenshot of that scene, cropped it to show only the house, and then once again ran it through Google Lens.

 And this time, it actually did find a perfect match.

It turns out the same house was used in a 2010 Tim Allen movie, and Tony Hoffarth, who posted a photo of the house on Flickr, also provided the address: 2005 Prosser Ave, Los Angeles. (Thanks, Tony!)

A simple Google StreetView confirmed that it was indeed the same place.

But Zillow has more photos here

Here is a StreetView from Google:

 
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