Luke Jacobs finished seventh in the women's half marathon at Two Oceans in Cape Town on 12 April 2026. Afterwards he posted a race photo on social media, and the bib on his chest read "Larissa". He had run on Larissa Parekh's number. The post tipped off Stuart Mann, a member of the Two Oceans board. When officials checked the chip data, they found a second swap. Nic Bradfield, another man, had finished tenth on a woman's bib.
Most marathon cheats are caught in ways as ordinary as that. A chip in the bib registers at timing mats along the course. A runner who skips a section leaves a gap in their splits, or a split nobody could run. Race photos show the wrong bib, swapped kit or a runner who has barely sweated. Much of the checking is done by people outside the race office. Other runners notice things, and Derek Murphy reads race results from home for his site Marathon Investigation. After a catch come disqualification, bans and rewritten results.
Rosie Ruiz was caught without a chip
Rosie Ruiz crossed the line first among the women at Boston in 1980. She was credited with "a then-record time of 2 hours, 31 minutes, 56 seconds." Spotters at checkpoints along the route had been logging bib numbers. "Ruiz did not show up there, on videotape or in any of 10,000 photographs taken along the first 25 miles of the course," the AP later wrote.
Two Harvard students then said they had seen her join the race near Kenmore Square, about a mile from the finish. Bill Rodgers had noticed something else. "She wasn't sweating enough; she had on a heavy shirt; she didn't know about running."
Ruiz was stripped of her title eight days after the race. Jacqueline Gareau of Canada was declared the winner and brought back to Boston the next month to receive her due. The investigation also found that Ruiz's qualifier was fake. She had taken the subway during the 1979 New York City Marathon.
Every check that caught Ruiz is still in use. The photographs, the witnesses and the runner who doesn't look like she ran all turn up in cases forty years later.
What a timing mat records
Mats at the start and finish give each runner's chip time. The mats in between record the splits that show where each runner was along the way.
The Mexico City Marathon in 2017 shows what that looks like across a whole field. The course had eight intermediate mats, roughly one every 5 km. Murphy went through the results. More than a third of the 27,873 runners missed at least one mat, and 291 missed all eight.
The last mat, about 1.4 miles from the finish, was missed by only 4% of runners. Every other mat had been missed by at least 10%. People were leaving the course and coming back for the end.
Murphy also picked out the 1,296 runners in that race who appeared to have run a Boston qualifier. More than two in three of them had missed at least one mat.
He was careful about what a gap proves. His figures held "if the data picked up by the mats is accurate." He allowed for "timing error or cheating."
Mexico City disqualified thousands of runners
The race's own website listed 5,806 runners as disqualified from the 2017 edition. The next year the organisers reported 3,090 disqualifications. Murphy thought the 2018 figure was too low, and by his count about 5,122 runners were removed from the results.
The organisers' 2023 review shows how a race works through a field that size. Their analysis of the runners' chips found "ausencia de registros en los puntos de control ubicados cada cinco kilómetros", meaning no record at the checkpoints placed every five kilometres. The Mexican sports paper Record reported that they were considering disqualifying more than 11,000 runners. The final count, the organisers told CNN, was 1,807. No team of marshals on the road could have checked that many runners by eye.
World Athletics said the organisers "had the proper checkpoints in place." It added, "It is always disappointing to hear that people choose to cheat in our sport."
Photos catch what the mats miss
A timing mat records that a chip went past. It cannot tell who was carrying it.
At Comrades in 1999, Sergio Motsoeneng ran the first stretch of the race. He then swapped vest and shoes with his brother Fika inside a mobile toilet on the route. Later they swapped back so that Sergio could run the finish. He placed ninth, a result worth just under R6,000. Then a newspaper published photos from the race. The brothers wore their watches on opposite wrists. The Comrades Marathon Association suspended both of them for ten years, according to the South African outlet OFM.
Murphy described a couple who moved the chip instead of the runner. The wife would "peel the chip off her bib and give it to him, and he would carry it across that last timing mat." The mats recorded identical splits for the two of them. The finish photos showed the husband crossing alone, with his wife miles behind.
Derek Murphy hunts cheats from home
Murphy started Marathon Investigation in 2015. He had been following threads on the LetsRun forum about a runner named Mike Rossi. After a big race he works through the results with finish photos, Strava files, eyewitness accounts, anonymous tips and an algorithm. "I think most people aren't aware of how much cheating goes on in marathons," he told NBC News in 2017.
Much of his work concerns Boston entries. At Philadelphia in 2016 he found 12 runners who appeared to have qualified for Boston by taking a shortcut. Among the 2015 Boston finishers he found 47 suspected cheats. The same names come back. "We find them multiple times...find the same people cheating year after year, race after race."
What happens to a runner who gets caught
A caught runner is disqualified, and the time comes off the results along with any place or prize it earned. In Mexico City in 2023, the city's sports institute said it intended to invalidate the times of the runners concerned.
At Two Oceans the women who lent their bibs were punished too. Both apologised and face two-year bans from the event, the AP reported. According to EWN, the two men faced a disciplinary process likely to end in two-year bans as well. Mann also gave a medical reason for the rule. A swap, he said, "poses health and medicals risks in case of an emergency as wrong medication may be administered to a wrong person." The medical team at the Falmouth Road Race has warned that a transferred bib keeps the original runner's emergency contact. Its medics "may not be able to determine their true identity."
A swap at Boston carries a penalty written into the entry itself. The B.A.A. participant agreement for the 2027 race says runners will not "transfer your official bib number or timing device." Doing so "would result in your and your transferee's disqualification from this and future competitions."
Frank Meza was disqualified twice at the California International Marathon for irregular splits. After the second time, in 2016, the race banned him. In 2019 he ran 2:53:10 at Los Angeles. The organisers there said footage "showed that the retired physician left the course for a portion of his run." Meza said he had left the route briefly to find a bathroom. Days after the disqualification he was found dead in the Los Angeles River.
When a cheat comes off the results, the runners behind move up. At Two Oceans, two women who had finished just outside the top 10 of the half marathon were moved into it.
Further reading
- Rosie Ruiz, Boston Marathon course-cutter, dies at 66 (AP via WBUR): the 1980 case, the 10,000 photographs and the witnesses.
- Thousands accused of cheating at the Mexico City Marathon (Marathon Investigation): Murphy's mat-by-mat analysis of the 2017 race.
- Mexico City Marathon 2017 disqualifications (Marathon Investigation): the race website's count of 5,806.
- Mexico City Marathon 2018 disqualifications (Marathon Investigation): why Murphy put the real figure at 5,122.
- Mexico City Marathon organisers dispute disqualification reports (CNN via ABC17): the final count of 1,807 for 2023 and the World Athletics response.
- Organisers consider disqualifying more than 11,000 runners (Record, in Spanish): the checkpoint data behind the 2023 review.
- Two men caught competing in the women's category at Two Oceans (AP via KWTX): the 2026 bib swaps and the bans.
- Bib-swapping scandal rocks Two Oceans Marathon (EWN): the disciplinary process facing the two men.
- The danger of bib transfers (Falmouth Road Race): a race medical team on what a swap does in an emergency.
- 2027 Boston Marathon participant agreement (B.A.A.): the bib-transfer rule and its penalty.
- Sergio Motsoeneng admitted to cheating at Comrades (OFM): the 1999 swap and the watch photos.
- How marathon investigator Derek Murphy catches cheaters (NBC News): his method and his Boston findings.
- Disqualified LA Marathon runner Frank Meza found dead (CBS LA): the Meza case and his earlier bans.
