The red notebook Cindy Stevenson found on the floorboard of her totaled 1999 Ford F-250 was part diary, part to-do list, presumably penned by an accused car thief who detailed his “master plan” to make $100,000 by stealing and selling catalytic converters.

Stevenson’s pickup was stolen from the parking lot of her SeaTac condo building in early December. Normandy Park police arrested the suspected thief 12 days later after he crashed the Ford into another vehicle. Officers found a catalytic converter, cut from the undercarriage of an SUV in Burien, on the pickup’s front passenger seat.

Stevenson, an Alaska Airlines pilot, found the notebook when she went to an impound yard to inspect the damage to her truck. She photographed the notebook’s pages — which included payouts the author received for stolen catalytic converters and lists of vehicles and parking lots to target — before turning it in to police.

“It’s definitely becoming more and more prevalent,” Normandy Park Police Chief Dan Yourkoski said of catalytic converter thefts.

He’s seen reports of thieves brazenly hitting vehicles parked at shopping centers during the day and in private driveways in the middle of the night. In some cases, he said, catalytic converters are being cut from stolen vehicles before they’re abandoned.

Though there aren’t any statewide stats on the numbers of stolen catalytic converters — or “cats,” as they’re commonly known — recent tallies from the King County Sheriff’s Office illustrate the surge that’s prompted lawmakers to consider legislation aimed at curbing thefts and figuring out where the stolen parts are ending up.

In 2019, the Sheriff’s Office received 11 reports of catalytic converter thefts. That number jumped to 285 in 2020, before skyrocketing five-fold to 1,425 last year.

The dual prospect of low risk and high reward seems to be driving the spike in catalytic converter thefts in King County and elsewhere, aided by pandemic-era restrictions on jail bookings for some people arrested for committing property crimes, say law enforcement officials. Vehicle thefts are on the rise again, too, an increase police say is likely linked to the skyrocketing thefts of catalytic converters.

At a time when police are increasingly focusing stretched resources on investigating violent crime, police say reforms that went into effect in July are also having unintended consequences: Officers can no longer use force to stop someone from walking away during questioning if they haven’t established probable cause that a crime has been committed and they can’t pursue vehicles — even stolen vehicles — unless there is a public safety threat or they have probable cause for certain violent crimes and sex offenses.

“What we’re hearing is increasing frequency of persons not stopping for traffic stops and acknowledging to law enforcement and to others that the word is out, that you don’t have to stop for law enforcement if they try to pull you over,” said Steve Strachan, executive director of the Washington Association of Sheriffs and Police Chiefs (WASPC).

He thinks that attitude change is behind the rise in stolen vehicles across the state. In November, 3,356 vehicles were reported stolen, a 52% increase over the 2,200 vehicles that were reported stolen in July, when the new laws went into effect, Strachan said.

All told, 12,599 vehicles were reported stolen in King County last year, accounting for 40% of the statewide total of a little over 31,000 vehicles — the kind of numbers not seen since auto thefts in the state hit peak rates between 2002 and 2007, according to data provided by WASPC.

Though the nexus between stolen cars and catalytic converters isn’t always clear cut, there’s anecdotal evidence indicating a link, said State Patrol Capt. Neil Weaver.

“Generally, people who are going out and committing crimes, if they do it in their own vehicles, they’ll get caught faster” because witnesses or surveillance cameras are likely to spot or capture license plate numbers that help people identify suspects, he said. “So if someone is going to steal a bunch of catalytic converters, the first thing they’re going to do is steal a vehicle.”

Dirty, super-heated air from a car’s engine passes through the honey-comb chambers of a catalytic converter before entering the muffler and exiting through the tail pipe. Coated in a ceramic or aluminum oxide wash that contains precious metals — namely platinum, palladium and rhodium — the metals act as catalysts and convert harmful carbon monoxide and nitrogen oxide into water vapor, carbon dioxide and nitrogen.

It’s possible to drive a car without a catalytic converter but it isn’t advisable or legal, said Seattle mechanic Christopher Goodwin. Without one, exhaust is pumped out beneath the car instead of through the muffler and tailpipe — the noise alone is enough to make your ears ring but could also start a fire, possibly lead to carbon-monoxide poisoning or cause additional damage, he said. In some models, Goodwin said the car’s computer will detect a problem and put the vehicle in “limp mode,” making it impossible to drive at full speed.

A catalytic converter stolen from some hybrid models can sell online for as much as $1,500 because it contains a larger amount of rhodium, which is resistant to corrosion and currently sells for more than $15,000 an ounce. That makes it eight times more valuable than gold, according to prices listed on KITCO.com, a leading online retailer of precious medals. As of Tuesday, KITCO.com priced platinum at $1,024 an ounce, and palladium, at $2,190 an ounce.

Thieves, on average, can earn $200 per catalytic converter — about 1/10th of what it costs to replace a stolen one. And thefts happen quickly, usually taking only a minute or two. Unless a thief is caught in the act, it’s nearly impossible for police to prove a catalytic converter is stolen because the parts don’t come with any identifying markers.

Though one suggested fix is for car owners to have their vehicle-identification numbers etched onto their catalytic converters, scrap-metal recyclers say that may do more harm than good, enabling thieves to access personal information about a vehicle’s owner, said Des Moines Mayor Matt Mahoney.

Mahoney was among those who testified earlier this year in support of HB 1815, which would require a Joint Transportation Committee work group to make recommendations to reduce catalytic converter thefts, require WASPC to establish a police training program (once it’s funded) to target metal thefts, and require scrap-metal dealers to document that any catalytic converters they purchase came from a vehicle registered to the seller. (Scrap-metal businesses are already subject to statutory requirements related to record-keeping, restricting certain transactions and an obligation to aid police in preserving evidence of stolen property.)

“We need federal legislation on re-sellers,” since online sites like craigslist, OfferUp and EBay and out-of-state buyers aren’t required to follow the same regulations as Washington’s scrap-metal dealers, he said. “Fencing stuff has been made easier and there’s no ramifications.”

Des Moines, a 7-square mile city in South King County with a population of about 30,000, saw 12 catalytic converter thefts reported to police in 2020, Mahoney said. Eighty-two thefts were reported to police last year through October, though Mahoney suspects the number is much higher with far more thefts going unreported.

Stevenson, the Alaska Airlines pilot, lives in Yakima but also owns a small condo in SeaTac, a half-mile from the airport. She drove her husband’s 23-year-old pickup across Snoqualmie Pass on Dec. 9, arriving at her condo that afternoon before an early-morning flight the next day.

“At 9 p.m., I looked out the window and the truck was gone. I couldn’t believe my eyes,” said Stevenson, who reported the theft to SeaTac police.

Early on Dec. 21, two Normandy Park police officers responded to a report of a suspicious vehicle blocking a driveway, which turned out to be Stevenson’s pickup, according to charges filed against Scott Sipaseuth, 30, of Tukwila. The driver ignored the officers’ commands to exit the vehicle, lit a cigarette and drove directly at one of the officers, who had to jump out of the way to avoid being hit, the charges say.

The driver fled in the pickup, damaging a patrol car and then driving into oncoming traffic at high speed before running a red light and crashing broadside into another car, the charges say.

The notebook Stevenson later found on her floorboard prompted her to join the Facebook group PNW Stolen Cars, where people post information and photos about their stolen vehicles and pass along tips to one other when a suspected stolen vehicle is spotted.

“I always thought vehicle thefts were random, but they’re not,” said Stevenson, who shared photos she took of the notebook with The Seattle Times.

“BLADES” is written across the top of the notebook’s first page, followed by an entry indicating the author’s preference for Diablo brand, medium and thin metal saw blades. Replete with spelling errors, profanity and capitalized words, subsequent pages include payouts the author received for catalytic converters and lists parking lots and vehicles to target:

“CRAWL UNDER THE FENCE BEHIND THE TRANSIT CENTER ON RAINIER. THE LOT IS FULL OF VEHICLES THIS TIME!” reads one entry. “TRANSIT CENTER LOT — THAT SHOULD BE ABLE TO FULLFIL (sic) MY GOAL FOR TONIGHT!”

A white van seen at a church, an SUV parked near a gas station on South Orcas Street, and trucks and work vans spotted in Tukwila’s Southcenter neighborhood were among the vehicles apparently on the author’s radar.

With only liability insurance on the pickup, Stevenson said the theft cost her $50,000 — the pickup was valued at $20,000 and she spent $30,000 on a replacement vehicle. But the emotional expense was worse.

“It’s the memories. It was my husband’s first truck before we got married,” and he had just installed a new stereo as an anniversary present to her, Stevenson said.

Catalytic converter thieves have hit Troy Bucy’s fleet of vans and box trucks so many times in the past three years that he now budgets $20,000 to $30,000 each year for replacement parts.

Bucy is the owner of Pacific Modular, a commercial flooring company in Renton. His is one of 30 or so businesses located at the Oakesdale Commerce Center, a 20-acre industrial park.

Pacific Modular’s crews typically work at night, said Bucy. But that hasn’t stopped thieves from stealing catalytic converters from the 16 vans and box trucks in the company’s fleet during the day or on weekends. Though Bucy parks some of his vehicles in a warehouse, there isn’t room for all of them.

Bucy estimates he’s had at least 30 catalytic converters stolen in the past three years and said many of his neighbors have been hit too. He spent $3,000 to replace two catalytic converters taken off one truck in December.

“It’s super scary — you turn on your vehicle and it sounds like a jet engine taking off,” Bucy said. “My guys are so used to it now.”

But it’s not just about the hard costs of replacing the stolen parts and paying his mechanic to install them, he said. With supply-chain issues, there are also soft costs to consider, since a single truck can be down for two or three weeks if a catalytic converter can’t be sourced right away.

“Because of thefts in the area, we don’t lock any of our vehicles because they’ll just break the windows if they’re stealing more than catalytic converters. It’s a mess. You feel helpless and that there’s nothing anybody can do,” Bucy said. “I get angry but that doesn’t do any good. We figure it’s the cost of doing business.”

Sara Jean Green: 206-515-5654 or sgreen@seattletimes.com; on Twitter: @SJGTimes.