Kenya's former world marathon record holder Wilson Kipsang has been given a four-year ban from the sport following whereabouts failures and tampering by providing false evidence and witness testimony.
Kipsang was provisionally suspended in January after being charged with two breaches of anti-doping rules.
The Athletics Integrity Unit (AIU) said Kipsang had committed four whereabouts violations.
This included a missed test on April 27 in 2018 and a filing failure related to whereabouts information for January 18 in 2019.
Kipsang also missed tests on April 12 and May 17 in 2019, the AIU said.
Three failures within a 12-month period can lead to a ban.
The second charge was related to providing "misleading information and evidence" to the AIU in his explanation related to the last two missed tests in an "attempt to obstruct or delay the investigation".
Kipsang had claimed the missed test on May 17 had been caused by a traffic accident, which had allegedly caused a traffic jam.
The accident was claimed to have involved an overturned lorry.
Kipsang provided a photo of the crash and AIU obtained information which found the image came from an accident reported on August 19, three months after the missed test.
"The AIU considers that the evidence demonstrates overwhelmingly that the athlete was engaged in tampering or attempted tampering in breach of the IAAF rules," the AIU said.
"The athlete engaged in fraudulent and deceitful conduct by providing deliberately misleading and false information to the AIU in an attempt to obstruct and delay the investigation into his explanation and/or prevent normal procedures from occurring, namely the recording of a missed test against him."
Kipsang's four-year sanction has been backdated to the start of his provisional suspension on January 10.
The @WorldAthletics Disciplinary Tribunal has banned long-distance runner Wilson Kipsang of Kenya for 4-years with effect from 10 January 2020 for Whereabouts Failures and Tampering by providing false evidence and witness testimony.— Athletics Integrity Unit (@aiu_athletics) July 3, 2020
Read more⬇️https://t.co/cBkQOqSHT4#AIUNews pic.twitter.com/To3OlnPkdt
Kipsang's management agency Volare Sports said the 38-year-old will consider an appeal to the Court of Arbitration for Sport (CAS).
"Volare Sports and Wilson strongly believe in a clean sport and support anti-doping measures for a 100 per cent," the company said.
"We emphasise that there is no case of use of doping.
"No prohibited substance was ever found.
"The accusation regarding alleged/attempted tampering (article 2.5) concerned an explanation that was given in the results management process regarding a possible whereabouts failure and did not concern tampering with a doping test itself.
"The decision is not final and conclusive yet.
"Wilson has the opportunity to appeal the decision at the CAS.
"We will study and analyse the decision of the Disciplinary Tribunal and consider the further legal steps.
"Pending this process we will not communicate anything more about it.”
Kipsang set the marathon world record time in Berlin in 2013, completing the race in 2 hours 3min 23sec.
A year earlier, he had won the Olympic bronze medal at London 2012.
The 38-year-old is also a two-time London Marathon champion, having won in the British capital in 2012 and 2014.
Kipsang has two other World Marathon Majors wins to his name following success at New York City in 2014 and Tokyo in 2017.
He is the only athlete to have ever beaten the current world record holder Eliud Kipchoge over 26.2 miles.
The AIU organised an anti-doping conference with Athletics Kenya last year, amid ongoing concerns over the number of Kenyan runners being sanctioned for doping offences.
Kipsang was among those to attend and posted on social media following the event.
Kenya is one of seven countries classed in Category 'A' by the AIU in relation to their doping risk.
Category A nations are both successful at international level but present a "high absolute doping risk".
Fifty-five Kenyan athletes are currently serving suspensions, according to the AIU database.