Thai police claim the first person they arrested in the investigation into the Bangkok bombing is the same man who planted explosives that ripped through rush-hour traffic in August, killing 20 people.

Adem Karadag, 28, was arrested last month in outer Bangkok after police said they found stacks of fake passports and bomb-making materials in his apartment. Authorities at the time released a photo of the man’s passport, which appeared to be badly made and possibly forged, showing him to be a Turkish citizen.

“He accepted the crime,” police spokesman Prawut Thawornsiri told reporters. “All the information we have leads back to him,” he said. Karadag is suspect of being the man in a yellow T-shirt who was captured on grainy security camera footage placing a black backpack by a bench on 17 August, moments before the blast.

Prawut said Karadag then sped away on a motorbike before changing his clothes at a toilet in Bangkok’s Lumpini park. He faces eight charges, including premeditated murder.

On Saturday, police escorted Karadag on a public reenactment of the bombing at the Erawan shrine in Bangkok’s central Chidlom district.

Public re-enactments are common in Thai police investigations although they have been condemned as suggesting the suspect’s criminality and also putting those accused at risk of attack from angry members of the public.

Flanked by armed commandos, Karadag wore a bullet-proof vest for his own safety and a yellow T-shirt. It was not clear if police ordered him to wear the T-shirt or if he chose it himself.

The shrine was closed for four hours and the central intersection was blocked to traffic for an hour. Karadag was escorted into the shrine, placed a black backpack he was wearing by a bench, and left in a multi-car convoy.

Thai police "bomb squad" sweep Erawan shrine ahead of main suspect reenactment pic.twitter.com/KgKabbX3ha — Oliver Holmes (@olireports) September 26, 2015

Karadag’s lawyer, Chuchart Kanphai, has previously said his client was born in China but moved to Turkey in 2004. He entered Thailand on 21 August, four days after the bomb blast, the lawyer has said.

He says his client’s full name is Bilal Mohammed although Thai authorities still refer to him as Karadag.

Thai police have been criticised for releasing confusing and contradictory statements throughout the investigation and for awarding themselves 3m baht (about £55,000 or $84,000), for making an arrests.

Another arrested suspect, Yusufu Mierili, is accused of handing the explosives to Karadag at a train station. Police also conducted a public re-enactment with Mierili earlier this month at Hua Lamphong train station. Mierili also wore a yellow T-shirt despite the fact that police have not accused him of being the man in the yellow T-shirt.

More than 120 people were wounded in the blast, the worst peacetime bombing in Thai history.

The government feared it would damage the country’s reputation as a tourist haven. Dedicated to the Hindu god Brahma, the Erawan shrine is also popular among Buddhists, and receives thousands of Chinese tourists a year. Many of the fatalities were Chinese nationals.

The shrine sits on a corner of a central Bangkok intersection, near suit tailors, five-star hotels and restaurants.

Thai police have said the attack was not politically motivated and blamed a criminal gang that trafficked Uighur Muslims from China to Turkey. They said the group carried it out in retaliation for a crackdown on their trade.

Many Uighurs, an ethnic minority in western China who have suffered persecution and abuse, have fled to Thailand in the hope of travelling on to Turkey, which has strong cultural links to the group and has sheltered them for decades. They have been prevented from travelling directly from China.

In July, Thailand forcibly returned 109 Uighurs to China, causing an international outcry and anger among the Uighur community.

Observers speculated that the bombing may have been carried out by a Uighur political group, given the high number of Chinese deaths. Karadag’s lawyer says his client was born in Xinjiang, the Chinese province where Uighurs are from.

No group has claimed responsibility for the attack.