Florida divers go deep with sonar to find sunken cars, solve cold-case mysteries
TAMPA — There’s a car down there, deep in the muck of the Hillsborough River. Maybe a motorcycle.
They found it the other day, out on their little boat with their fancy fish finder: a shadow on the sonar with a golden blob in the center.
Now, on a warm winter afternoon, they’re wriggling into wetsuits below the 40th Street bridge, about to dive for a license plate.
“Could be stolen,” says John Martin, 55.
“Could be a homicide,” says Mike Sullivan, 44. “You never know. There could be a body in the trunk.”
In the last two years, the half-brothers who own Sunshine State Sonar have found more than 350 cars in canals, ponds and waterways across Florida.
Weekend fishermen turned amateur underwater detectives, the true-crime junkies dive into cold cases, searching for the disappeared. Sometimes, they choose the cases themselves, following threads online. Other times, law enforcement asks for their help.
They have discovered remains of 11 missing people inside cars, giving answers to relatives who had spent years agonizing.
One family, who thought their mom had left them, learned that she had driven off the road. Relatives of a missing teacher suspected his girlfriend — then found out he had been submerged in a canal for three years. And the son of a young mother who thought she had been murdered was relieved when her death proved a watery accident.
“You good?” Sullivan asks Martin, who is checking his air supply. Martin gives a thumbs-up.
They shove off, motoring toward a bobbing red buoy where they had marked the spot days before.
Sullivan splashes into the gray-green water, sinking through silt so thick he can’t see, feeling his way through the dark.
• • •
Martin owns a pool cleaning company in Lakeland. Sullivan, the leader, runs an auto parts business from his Gulfport home.
They both speak excitedly, spewing staccato sentences with thick Boston accents that haven’t ebbed after two decades in Florida.
“It all started with YouTube,” Sullivan says. “I kinda got obsessed.”
A couple of years ago, he got into bingeing Adventures with Purpose, videos of a volunteer dive team in Oregon that searches for missing people.
“Florida has so much water!” he told his wife. “I really need to do this.”
Sullivan has always owned fishing boats, loved catching king mackerel. He raced personal watercraft, flew airplanes, learned to read complicated instruments to navigate through the dark. A former mechanic, he knows car makes and models, can recognize hubcaps and bumpers.
And he doesn’t just watch true crime, says his wife, Johanna. “He has to go to the scene to see for himself, if it’s in Florida. He just has to be there, especially for missing people.”
He didn’t know how to scuba dive. He’d never longed to float through crystal water or over schools of colorful fish. But he got certified so he could swim through muddy channels and search waterlogged crime scenes.
He bought a shallow-draft boat and outboard motor, rigged it with the latest fish-finding technology: a Lowrance SideScan sonar, a DownScan imaging device and a Garmin LiveScope. The machines send sound waves pulsing through the water, then record them as they bounce back to create a blurry image on a monitor — like a sonogram.
It’s similar technology to what authorities are using to scour the waters off of the collapsed Francis Scott Key Bridge in Baltimore, where search crews were able to detect at least five submerged vehicles.
The equipment cost Sullivan $21,000. It took him a year to be able to interpret the images, to tell a rock from a Volkswagen. He learned that small cars sink fast and SUVs, which have bigger air pockets, sometimes float.
“He’s always been high-energy, seeking adventure,” says Sullivan’s wife, who has been with him since they were 18. “Only now it has meaning.”
He started close to home, in Pinellas County, by reaching out to a cold-case detective. The officer told him about Robert Helphrey, 34. In 2006, after closing the Palm Harbor seafood restaurant where he worked, he went to a pub. Friends watched him drive away around 1:30 a.m., but no one ever found Helphrey or his Mitsubishi hatchback.
“He was a dad, a veteran,” Sullivan says. “He just disappeared.”
Over the next year and a half, Sullivan searched 150 bodies of water in Pinellas, Pasco and Hillsborough counties. “My friends and family thought I was crazy,” he says. “They were taunting me. One sent a Where’s Waldo? T-shirt.”
Sullivan reached out to Helphrey’s mom and daughter. Finally, last April, as the family looked on in shock, he found Helphrey’s car under 10 feet of water in a retention pond. For 17 years, his body had been submerged just a few miles from his home.
Sullivan doesn’t go fishing, ride personal watercraft or fly planes anymore. All of his free time goes toward searching.
Once a month, Sullivan, Martin and a couple of other volunteers go on expeditions, paying their own expenses. Last year, Sullivan says he spent $27,000 on Airbnb rentals across the state. Videos from their YouTube channel bring in about $100 a month.
“We’re blessed to have good income,” he says. “I just wish we could get a grant or something to do this full time.”
• • •
The car is upside down in the elbow bend of the Hillsborough River, nose-first, buried in sand up to its door handles.
Sullivan switches on a flashlight strapped to his left arm, takes out his phone in its waterproof case.
Swimming closer, 20 feet below the surface, he can make out a Cadillac, not too old, maybe black? The model: CTS.
On the back, there’s a Buccaneers plate — with a registration sticker valid until April 2024.
This can’t be the vehicle we’re looking for, Sullivan realizes.
A neighbor had called recently, concerned about an accident from 2019, where someone seemed to have gone over the guardrail.
This Cadillac’s demise must have been recent. Its windows are so caked over, it’s impossible to tell if anyone is inside.
“Could be an accident,” Martin says as their boat putters back to land. “Or insurance fraud.”
Sullivan nods. “Or suicide.”
Onshore, they peel off their wetsuits and call the cops.
• • •
The stories haunt Sullivan — those he has helped solve and those that elude him.
He thinks about missing people while he’s in the car line, waiting to pick up his kids. They keep him up at night, beside his sleeping wife.
When he finds someone, he offers their relatives a chance at closure. But he also quells whatever hope they might have left. “Calling families is the worst part,” Sullivan’s wife says. “He’s not trained to be a grief counselor.”
Every time Sullivan drives over a bridge, or around a cloverleaf with a retention pond, along every canal he crosses, he wonders: Could someone be down there?
Imagine driving along, he says, then suddenly sinking into dark water, trapped behind the wheel.
He researches newspaper archives, looks up police reports, scans maps and highway markers. In his phone, alongside family photos, Sullivan keeps pictures of the missing. He has memorized their faces and names, can recite when each person was last seen, and where they might have been driving.
Sandra Lemire was a single young mother, heading to a date at a Kissimmee Denny’s 12 years ago. She had borrowed her grandmother’s red minivan and promised to call on her way home.
Her family worried she had been kidnapped or killed.
Sullivan spent more than a year working with Orlando police as divers searched 63 bodies of water. In December, newly released cellphone records helped map Lemire’s drive. Sullivan’s sonar picked up the minivan in a retention pond off the Interstate 4 exit to Disney World. Her remains were inside.
Kareem Demarzo Tisdale, 30, disappeared from his parents’ Fort Lauderdale home 19 years ago. In January, while searching for someone else in a pond at Sawgrass Mills Mall, Sullivan and divers from Adventures with Purpose found what they think is Tisdale’s 1983 Oldsmobile. Police are testing DNA of the water-logged skeleton.
“The one that really got me, that I went through weeks of depression over, was Karen Moore,” Sullivan says. Less than 24 hours after the Davie-area mother filed a restraining order against her husband, she failed to pick up her daughter from Girl Scout camp. Sullivan found Moore inside her white Saturn 22 years later in a pond near her house.
In January, Sullivan says, they were able to “bring five people home” in six days.
• • •
“It’s a Cadillac down there,” Sullivan says, handing the bent metal plate to an officer. Ten cops have shown up, including Tampa police divers. Beneath a grove of live oaks, they stare at the sodden riverbank and the bouncing buoy, a football field away. The earth smells like wet leaves.
The ground is too wet, the slope too steep for a tow truck, the officers decide. “We’ll have to come back,” says Chris Audet, who coordinates the dive team. “Shut down the bridge and hoist it up from there.”
Running the plate, the cops learn that the 2013 Cadillac was stolen a few months ago in Hillsborough. “Great job,” Audet tells Sullivan and Martin. “We don’t have the time to go fishing like this.”
Be careful in the water, the officer tells them. “There are lots of dinosaurs out there.”
“Only the little gators come up to us,” Sullivan says. “At least so far.”
“I wouldn’t dive these ponds for golf balls,” he went on. “But knowing that we can make such a huge difference for some of these families …” He shook his head and wiped his eyes.
• • •
A couple of weeks later, five Tampa police divers drop into the Hillsborough River. The sun is bright, the air and water both 60 degrees. Their teeth chatter.
“We don’t know what could be in there,” Sgt. Charlie Feldman tells them. “Weapons? Remains? We can’t search it without lifting it.”
Every year, Tampa police recover about a dozen cars from waterways, Feldman says. But this process is more complicated because of the shore’s steep slope.
Recovery takes three hours. Divers attach straps and air bags to each of the car’s tires, then inflate them until the vehicle floats. A police boat pulls it to the bridge, where two tow trucks are waiting.
“It’s kind of cool,” says Ashley Maggart, 38, who is filming. “But it’s sad at the same time.”
Maggart, a mother of four, had called police about the damaged guardrail near her home years ago. When they didn’t investigate, she messaged the Sunshine State Sonar crew.
A boom hoists the car 30 feet above the bridge. Black mud, oil and water drain out, staining the river with a rainbow sheen, filling what looks like a swollen bladder dangling below.
“Oh, is that a head?” Maggart cries. “What’s in there?”
She sends a video to Sullivan, who is on spring break with his kids. He can’t believe he’s missing this.
“There’s a key in the ignition, but it’s corroded,” Feldman says. “After two weeks in water, any DNA evidence would be erased.”
He checks the glove box and back seat, which stink of decay, then shines a light into the trunk: Soggy paperwork. A water bottle. Otherwise, empty.
“If someone is in that river, their loved ones deserve to have that closure,” Maggart says. “Even if it’s just someone’s stolen vehicle, they deserve to know.”
• • •
The next weekend, Sullivan and his crew find two more cars in the Tampa Bay Bypass Canal. Next up, a trip to Miami.
“We got 53 cars we’ve located just in south Florida that we haven’t been able to dive on yet,” Sullivan says. “So many cases are still unsolved.”
Like Carlton McCarthy Ireland, who disappeared after leaving his Zephyrhills home to pawn a ring in Tampa.
And Peggy Wynell Byars-Baisden, 23, a mother of three, last seen in 1965 in a parking lot in Polk County.
Then there’s Brenda Starr, 32, who vanished from Palm Harbor in 1995 after dropping her daughter off at school. Sullivan has been searching for her Mazda Protege since he started diving.
Recently, he has been talking to her 82-year-old mom. He’s promised he’ll do everything he can to bring Brenda home.
