Former teacher Jomsap Saenmuangkhot, 55, speaks to reporters on Friday after hearing the Supreme Court's rejection of her request for a retrial she had requested to clear her name in a fatal hit-and-run case that left her in jail for a year and a half. (Photo by Patanapong Sripiachai)

An inquiry panel will be set up to prepare legal action against a group of people who allegedly helped provide false witnesses to back a former teacher's claim of innocence over a deadly car crash.

Pol Maj Gen Suwicharn Yankittikul, chief of Nakhon Phanom provincial police, said the panel will focus on a group that gave false testimonies to a court to seek the retrial of Jomsap Saenmuangkhot.

The police action comes after the Supreme Court on Friday rejected Ms Jomsap's petition seeking the revival of the fatal car accident case in which she was sentenced to three years and two months in prison by the Supreme Court in 2013.

She was found guilty of recklessly driving a pickup truck that struck a bicycle, killing Lua Pobamrung, in Nakhon Phanom's Renu Nakhon district in March 2005.

Following a royal pardon in April 2015, Ms Jomsap pursued a wrongful conviction case with the Justice Ministry in line with the 1983 Retrial of Criminal Case Act. The Ministry of Justice later agreed to help seek a retrial, making this the first case in 34 years since the legislation was promulgated.

In dismissing the petition, the Supreme Court said it suspected there was a network that hired out people to confess to crimes they did not commit in exchange for payment -- in this case to back Ms Jomsap's claims of wrongful conviction.

According to the court, evidence and witnesses that were brought to the hearing by the legal team representing Ms Jomsap were neither new nor reliable and the witnesses also gave conflicting testimonies.

One of Ms Jomsap's witnesses was a man called Sap Wapee, who told police that he was behind the wheel, not Ms Jomsap, when the pickup truck hit and killed Lua. However, Mr Sap was not brought to testify despite being a key witness.

Mr Sap was initially hired for up to 400,000 baht by a group of people for the false confession but he denied the group later approached another man identified as Prasert Roopsa-ard to hire him for 200,000 baht to testify that he was the driver, according to the court.

But after Mr Sap changed his mind or the group found that Mr Prasert could not drive, Mr Sap finally told police that he was the real driver.

The circumstances of the case suggested there was a procedure to hire people to make false confessions, the court ruled.

Pol Maj Gen Suwicharn said yesterday that the inquiry panel will thoroughly study the court's ruling and gather evidence to determine who was part of the suspected network.

"At this stage we can't say who will face legal action and what charges will be brought against them. But I can assure that police will take legal action. This is a really big case and the legal battle dragged on for a decade," he said.

He said the inquiry team, to be chaired by his deputy Pol Col Sakchai Satmareung, is being formed and is expected to start work in a few days.

Earlier, police said they suspected Mr Sap and Ms Jomsap's friend, Suriya Nualcharoen, who helped seek the retrial, were part of the network.

Pongsa Ratree, the Justice Ministry's lawyer in the case, said the rehabilitation process for Ms Jomsap has been terminated following the Supreme Court's decision.

He said police will investigate who was part of the network allegedly hired as scapegoats in exchange for payments, adding that Ms Jomsap could face charges depending on the evidence.

He said efforts to revive the case were initiated when she was serving the jail sentence. "The Justice Ministry has done its part," he added.