COLOMBO, Sri Lanka — Sri Lanka’s former navy chief said Thursday the father of two of the Easter suicide bombers has been arrested on suspicion of aiding his sons.
Jayanath Colombage, who now is a counter-terrorism expert at the Pathfinder Foundation, confirmed the arrest.
Sri Lankan police could not immediately be reached for comment.
Sunday’s coordinated suicide bombings targeted three churches and three hotels, killing at least 359 people and wounding 500 more.
Authorities have blamed a local group, National Towheed Jamaat, for the attack. The group was previously only known for vandalizing Buddhist statues and for the extremist online sermons of its leader, alternately named Mohammed Zahran or Zahran Hashmi.
On Tuesday, the Islamic State group asserted it carried out the assault, bolstering its claim by publishing images of Zahran and others pledging loyalty to IS leader Abu Bakr al-Baghdadi.
On Thursday morning businesses in Colombo advised staff to stay indoors until 2 p.m. because of a possible security threat and an ongoing search operation in the capital.
John Keells Holdings, the parent company of the Cinnamon Grand hotel, one of the sites stricken in the Easter Sunday bombings, sent an email to its staff on Thursday about the unspecified threat.
It was not immediately clear where the warning originated. A police spokesman was not available for comment.
Australia’s prime minister said one of the suicide bombers in the Sri Lanka Easter attacks had been in Australia years earlier.
Prime Minister Scott Morrison said the person had been in Australia on a student and a graduate skilled visa with a spouse and child visa as well. The individual left in early 2013.
Morrison told reporters the person’s Australian link was part of an ongoing investigation and wouldn’t comment further.
Separately, a British security official has confirmed one of the bombers was believed to have studied in the UK between 2006 and 2007. The security official, who spoke on condition of anonymity because of the sensitive nature of the investigation, said British intelligence was not watching Abdul Lathief Jameel Mohamed during his stay in the country. His name was first reported by Sky News.
Sri Lanka banned drones and unmanned aircraft as authorities continue controlled detonations of suspicious items four days after the series of suicide bombing attacks in and around the capital of Colombo.
Sri Lanka’s civil aviation authority said that it was taking the measure “in view of the existing security situation in the country.”
Hobby drones have been used by militants in the past to carry explosives.
Iraqi forces learned that they are difficult to shoot down while driving out the Islamic State group from northern Iraq, where the extremists loaded drones with grenades or simple explosives to target their forces.
Also Thursday Sri Lankan authorities detonated a suspicious item in a garbage dump in Pugoda, about 35 kilometers (22 miles) east of Colombo.