Police are investigating the mysterious disappearance of a notorious German businessman who went missing following a meeting in Thailand.

Hans Peter Walter Mack, 62, had met with a female German property broker named Peta, 54, on July 4 to discuss the sale of a pool villa on the island of Koh Samui and a boxing stadium in Chonburi.

The pair chatted and then went their separate ways but Hans never returned to his family in the Swiss Paradise Village in Pattaya.

On July 5, the businessman's incredibly glamorous and much young Thai wife Piraya Boonmak, 24, filed a missing persons report with the local police.

She said she had been living with Hans for five years, and that he had two sons with his previous wife.

She said: 'I knew that something was wrong because my husband is usually very punctual. He doesn't like to be late coming home because he knows it makes us worried.'

The family has also posted on their social media offering a three million THB (85,192 USD) reward for information leading to Hans's whereabouts, and an additional 100,000 Baht (2,840 USD) if informants could find the Mercedes-Benz E350 coupe he had been driving.

Police Colonel Tawee Kutthalaeng, superintendent of the Nong Prue Police Station, said investigators were gathering surveillance footage for the search. He said they found that Hans was last seen driving in the Chaiyapruk Soi 3 area of Chonburi.

Police summoned property broker Peta, believed to be the last person to see the missing German, to the station. She reportedly told officers that they had discussed buying properties worth several million U.S. dollars before separating. She said she had no idea Hans was driving behind her car.

On July 9, Police Colonel Tawee said that Hans's Mercedes-Benz had been found in a car park at the CC Condominium in Pattaya. However, the seats, windscreen, door, and door handles had been wiped with bathroom cleaner in an apparent attempt to tamper with evidence.

Speaking to local media, Police Major General Theerachai Chamnanmor, commander of the Investigation Division Provincial Police Region 2, said: 'There was an intention to destroy evidence and the case indicates that Mr Hans-Peter Walter Mack's disappearance was suspicious.'

Inside the car's boot were a pair of sandals and documents enclosed in an envelope. Officials have not disclosed the contents of the documents.

A restaurant owner and a grilled chicken vendor near the car park said they noticed the car sitting in the lot on July 6. They said two women had exited from the vehicle, one with dark skin and around 160 centimetres in height. They told police they did not know where the women were headed.

CCTV footage and phone signal tracing led officers to a rental house in the AChill Gardens village. Cops said the landlord was cooperative with the search, which yielded no suspicious findings.

Police Major General Theerachai said two foreign suspects were also summoned to the police station, but refused to provide details during questioning.

Police said they found an 'abnormal transaction of two million baht' but were unsure if it was related to Hans's disappearance.

The search for the missing German is still ongoing.

In February 2018, Hans was arrested in Sin City Pattaya along with a Thai woman Amornrat Kateuy on charges of allegedly prostituting girls under the age of 18. The police did not provide any updates regarding the status of this case.