Thai police said on Monday they were questioning another Iranian in connection with explosions in Bangkok this month that have been linked to an attack on the wife of an Israeli diplomat in India and another incident in Georgia at around the same time.
Iran has denied involvement but Israel has said the Quds Force, a covert arm of Iran's Revolutionary Guards Corps, was behind the bombings.
One Iranian, Saeid Moradi, lost his legs on February 14 when a bomb he was carrying exploded in Bangkok shortly after an apparently accidental explosion forced him and two other men to flee a house they had been renting.
He remains seriously ill in hospital. A second Iranian, Mohammad Khazaei, is in custody after being arrested at Bangkok's main airport and a third, Masoud Sedaghat Zadeh, is being held in Malaysia.
Thai Immigration Police Commissioner Wiboon Bangthamai told Reuters three Iranians had been arrested in the Nana area of Bangkok at the weekend but two had been eliminated from the inquiry.
The other, Madani Seyed Mehrded, 33, remained in custody because he had overstayed his visa and was being questioned for links to the bombing.
According to Thai media, police told a weekend news conference they had discovered call logs showing Mehrded regularly communicating with two of the other suspects, Moradi and Khazaei.
Police also said Mehrded had been waiting in front of the building housing the Israeli embassy on the day of the blasts.
Mehrded has denied any connection with the bomb incident.
Thai government and police officials have given conflicting views on whether the Iranians were planning to attack Israeli diplomats.
However, the police forensic unit commander has said the bombs in Bangkok resembled one used in the attack on the Israeli diplomat's wife in New Delhi on February 13.
Police are still looking into mysterious stickers bearing the word "sejeal" found at various points along a 1.5 km (2.4 mile) route in central Bangkok that may have some connection to the bomb incident. Similar stickers were also found at the house where the explosion occurred on February 14.
Media have speculated that they could have been used to mark out a route or to identify areas for attacks.
"We still cannot confirm nor deny whether the stickers were part of the February 14 plot. At the moment we are testing DNA found on the stickers," Immigration Police Commissioner Wiboon Bangthamai said.
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