We get a call once every couple of weeks for a cardiac arrest. That means someone called 911 saying the person is unresponsive and doesn’t seem to be breathing.

Usually, what actually happened is the person fainted and the caller panicked. Usually, the person is breathing.

But sometimes not.

We fly so fast I actually put on my seatbelt. “I’d like to have kids one day,” I tell my partner Bronson. He responds dryly, “You’ll speak when you’re spoken to.” Then he whoops the siren to get past a gypsy cab.

We stop at the corner of Cortelyou and East 35th Street, in the East Flatbush section of Brooklyn, at a rundown limestone with bay windows in an area of similarly rundown row houses. Judging from the ornately carved eaves and the broken stained-glass transoms, the houses were probably once quite lovely. I push open the front door and call, “Hello?”

The smell hits me immediately, sweet and sickly. The interior is like a shack, floorboards rotted in gaping holes, kitchen destroyed. There’s no electricity or heat – it’s dark and cold inside, the oven door open, the gas hissing.

A man approaches us from the dark recesses of what was once a formal dining room. He’s glassy-eyed and filthy, and introduces himself as the boarder. There’s a bare mattress on the floor where he apparently sleeps. He tells us he went upstairs to check on his landlord, and found him dead. “When did you last see him alive?” I ask.

The man thinks. “Wednesday, maybe Thursday.”

It’s Tuesday now. “Five days until you wondered if something was wrong?”

“I went up to his room to see if he needed anything.”

As I climb the stairs, the odor gets stronger. “Didn’t you smell anything before then?”

He sniffs. “I don’t smell anything now.”

I let it pass. “What’s his name?” I ask.

“Stewart Rice.”

“Can you find us any I.D.?”

He shrugs, turns around, and goes back down to look for some.

I pass the upstairs bathroom; everything is soiled. I push open the door to the bedroom.

The body is lying on its right side in bed. It’s large, about 500 pounds, and in the early stages of decomposition. Ulcers fester on the legs, the skin is bubbling and sloughing off, and there is dependent lividity (the blood pooled to the lowest areas of the body).The face is swollen and purple. The smell is like a wall. Five days.

“And it’s winter,” I whisper to Bronson. “Imagine if it was summer?”

Empty liquor bottles perch on every available surface. Given his weight, I wonder if he was able to go out and buy them himself, or if they were delivered.

The police arrive and together we search the bedroom for I.D. The female officer says she just ate lunch and feels sick. I give her extra gloves. “Come on,” I say. “Isn’t this why you became a cop?”

She smiles weakly. I find nothing to identify the deceased man, but she comes up with four empty medication bottles and a wallet covered with duct tape. “Excellent,” I say, and write the names of Stewart’s meds on my paperwork. “I promote you to detective.”

Then she hands me a startling piece of I.D. “He was a Merchant Marine.”

I take the card. “Not with that weight,” I say. “No way.” According to the I.D., he’s 50 years old. I would never have been able to guess that. A decomposing corpse is so unlike a living person that age, race, and identifying features go right out the window.

The boarder comes upstairs with a thick creamy envelope from the Romanelli Funeral Home. Sixteen years ago, Stewart’s mother, Gladys, died. Six years before that, his father, Frank, went. There’s a deed to the house in Stewart’s name, and a color snapshot of a good-looking young man, of normal weight, smiling, holding a little baby. I flip it over. Stewart with Michelle, 1982.

“That’s his daughter,” the boarder says.

“She must be 22 now,” I say, looking up. “Can you contact her?”

The boarder once again trudges downstairs.

We check Stewart’s body for signs of foul play (there are none), then peel off our gloves and go downstairs, where the cop whips out her cell phone and calls for the medical examiner to remove the body. I don’t know how they’re going to do it given his weight and level of decomposition, but that’s their business. I’m here to pronounce death, which I do, officially, at 12:20 p.m.

The boarder comes up empty-handed. “No phone numbers,” he says.

“Did he have a cell phone?” I ask. Maybe I could find his daughter’s number in there.

He shakes his head. “Michelle comes every couple of months. She used to come more often, but then Stewie got into the bottle.”

“How long has he been that heavy?”

The boarder thinks. “Ever since I’ve been here. About five years.”

“Was he mobile?” I ask. “Could he get around?”

He blinks. “Oh yeah, he used to walk every day.” He pauses. “To the bottle shop, to the Chinese food.”

“And you didn’t smell anything?”

He points to his nose. “Sinuses.” He scratches his head with tobacco stained fingers. “What’d he die of?”

“I’m not sure,” I say, “but given his weight and age, probably a heart attack.” I try to ease the ugliness of the situation. “Don’t look at what he looks like now,” I say gently. “It’s been five days.”

I notice a magnet on the radiator, a mini-calendar with the business card of a podiatrist. I flip open my cell phone and dial. After a series of explanations to receptionists, I get patched through to the doctor. I ask him if there’s a Michelle listed in Stewart’s files. There isn’t. There’s no one listed at all. The podiatrist seems genuinely sorry.

“So basically,” I tell Bronson, hanging up, “we have a John Doe with a name.” The medical examiner will perform an autopsy to determine the exact cause of death, and Stewart will be buried in a pauper’s grave. Michelle will discover what happened to her father when she next comes to visit. And the boarder will move on to another mattress.

Ms. Klopsis is an emergency medical technician for the FDNY.This column details her observations and experiences on the job. Some names and identifying details have been changed to protect the privacy of patients.