Yoo had been target of South Korea's largest manhunt; Failure of police to catch Yoo had been burden for Park government.
The body of South Korea's most wanted man, linked to the sinking of a ferry in April that killed 300 people, was identified more than a month after being found in an orchard, police said on Tuesday, with his book and empty bottles of alcohol nearby.
The police chief in charge of the case in a small city in the south of the country was sacked on Tuesday for not recognizing the book, or putting two and two together, and for not identifying the corpse earlier.
Police said that DNA and fingerprint evidence from the heavily decomposed body found on June 12 showed it to be that of Yoo Byung-un, 73, the target for more than two months of South Korea's largest manhunt.
Beside the body was a book written by Yoo, along with an empty bottle of a shark-liver-oil health tonic, made by a Yoo family company, and three empty bottles of alcohol, police said.
The book was called "Greater Love has No One Than This" and was written in 1995 while Yoo was serving four years in prison for fraud.
Yoo was a wealthy businessman who headed the family that owned the operator of a ferry that capsized in the country's worst maritime disaster in 20 years.
Police said they had not determined a cause of death but said it did not appear to have been foul play. Toxicology tests were under way.
The Sewol ferry, travelling too fast on a turn, sank on April 16 on a routine trip from the mainland to the holiday island of Jeju. Of the 476 passengers and crew on board, 339 were children and teachers from the same school on the outskirts of Seoul. Only 172 people were rescued and the remainder are all presumed to have drowned.
Failure of authorities to find Yoo had become a political headache for President Park Geun-hye, whose government came under heavy criticism for its handling of the disaster.
The Sewol's 15 surviving crew members, including the captain, are on trial on charges ranging from homicide to negligence. The disaster prompted an outpouring of grief and anger after some crew were caught on video abandoning ship while children, following instructions, stayed put in their cabins.
Yoo, also a photographer and co-founder a church which made its own organic ice cream, was accused of embezzlement, negligence and tax evasion. Authorities had offered a reward equivalent to nearly half a million dollars for information leading to his arrest and detained several family members.
Woo Hyung-ho, police chief in Suncheon, told a televised news conference that a book written by Yoo was found at the site, along with an empty bottle of a shark-liver-oil product.
"WE WERE NOT PERFECT"
Woo said police could have conducted forensic tests earlier had they managed to identify the two items.
"We didn't know at that time it was a book written by Yoo," said Woo, who later in the day was dismissed from his post, a Korean National Police Agency official said.
"We admit we were not perfect," Woo said.
Another police official said the announcement had been delayed as forensic investigation of DNA takes 40 days.
The time of death was unclear as the body had decayed by more than 80 percent. Media reported that the neck had been separated from the body, although a police official said that may have been the result of decomposition.
Police in Suncheon had suspected that the body might belong to Yoo and had twice tried to collect fingerprints, even cutting the five fingers off the left hand, but had failed to get usable prints, a police official told Reuters.
At around midnight on Monday, the DNA test results were finally returned showing a match with Yoo. Another attempt at taking a fingerprint from the refrigerated body was made, this time with the right index finger, and it matched a print of Yoo's that was on file, a police official said.
LIKE A HOMELESS PERSON
The body was found about two kilometers from a retreat that police had raided on May 25 on intelligence that Yoo was there.
"I was roaming around the field and a person was dead ... but the body was decayed," Park Yoon-seok, a resident who found the body, told cable news network YTN.
"He looked like a completely homeless person. He was lying straight with only the head turned around."
The announcement came less than 24 hours after prosecutors apologised for failing to capture Yoo when they released interim results of their investigation into the disaster.
They made no mention on Monday that a body suspected of being Yoo's had been found. Also on Monday, a court issued a fresh arrest warrant for Yoo, as an earlier warrant had been due to lapse.
Prosecutors in Incheon, west of Seoul, who are leading the investigation into the Yoo family, said their probe would continue. "Whether Yoo Byung-un is dead or not, we will proceed with the investigation," they said in a statement.
His sons, Yoo Dae-gyun and Yoo Hyuck-ki, were majority owners of the shipping company Chonghaejin Marine Co Ltd through an investment vehicle and had direct or indirect stakes in nine business affiliates connected to the Sewol.
Wanted posters for the capture of Yoo and his elder son, Yoo Dae-gyun, have been posted throughout the country.
The younger son, Yoo Hyuck-ki, has been based in the United States, where he controlled several businesses with links to Yoo Byung-un and his church, according to company records.
In their hunt for the elder Yoo, police had searched organic farms and retreats belonging to Yoo and his Evangelical Baptist Church and arrested church members on suspicion of helping Yoo escape. The church denied the allegations.
By Ju-min Park