Ploenchit Tomchitchong, the mother of Prakitpao Tomchitchong, owner of the well-known Applied Physics school filed charges against the four on Aug 20, 2007.
She accused Pemmika, 31, Ruthai Rungsirimethakul, 29, Nathapol Promprapai, 34, and Vathanyu Tanteerapong, 33, of cheating her son out of cash and valuables worth more than 9.6 million baht by exploiting his mental weakness between Oct 2006 and Feb 2007.
The lawsuit said Pemmika - with help from Ruthai, Nathapol and Vathanyu - had deceived Mr Prakitpao into giving them cash and valuables, including a 1.56 million-baht Toyota Camry car, a 245,000-baht Rolex watch, a 145,000-baht diamond ring and two pistols worth 130,000 baht.He also bought her a rare 9999 licence plate number for 980,000 baht at an auction; paid 150,000 baht in rent on her condominium; and put a 250,000 baht down payment on a house for her.
During the trial, medical evidence was submitted showing that Mr Prakitpao had been suffering from mental illness, so was easily led into believing in superstition and reincarnation by the four suspects, who convinced him that Pemmika could recall her past 99 lives, and that she and he were a couple before they were reborn. She told him that he had abused her in this past life, and said he should compensate her for the maltreatment, which led to Mr Prakitpao's decision to buy the vehicle and other items.
The Criminal Court on Oct 26, 2010 sentenced Pemmika to four years and six months in jail for fraud and attempted fraud, dismissing Pemmika's claims that the money and gifts were given out of love.
The three others were each sentenced to three years in prison, suspended for two years, and a fine of 27,000 baht. The four were also ordered to return more than 8 million baht to Mr Prakitpao.
Both the plaintiff and the defendants appealed, but the Appeals Court on Wednesday upheld the lower court's decision.
Pemmika said after the ruling that she has three children to care for and that her mother had paid one million baht in bail to allow her to stay at home since 2010, pending the outcome of today's appeal.
The bizarre case grabbed public attention because Applied Physics was a popular tutorial school at the time and Mr Prakitpao and Pemmika were close friends.
Mr Prakitpao's family had him admitted to a mental institution after he displayed signs of mental illness, but Pemmika filed a complaint with police claiming Mr Prakitpao was being illegally detained before his mother filed criminal charges against her and her three friends.
Investigations by police and Srithanya Mental Hospital later found that the tutor had a mental illness, likely to have been caused by an unusually high level of the stimulant ephedrine found in his body during medical tests.