The owner of the Bangladeshi factory building that collapsed, killing more than 370 people, has been arrested while attempting to flee to India, police said.
Mohammed Sohel Rana, a leader of the ruling Awami League's youth front, was arrested on Sunday by the elite Rapid Action Battalion in the Bangladeshi border town of Benapole, Dhaka district police chief Habibur Rahman told Reuters.
Police had put border authorities on alert and arrested his wife in an attempt to bring him out of hiding.
Speaking near the site of the wreckage of Rana Plaza, which housed several businesses making low-cost garments for western retailers, junior minister for local government Jahangir Kabir Nanak told reporters that Rana would be brought to Dhaka by helicopter. Rescue workers cheered and clapped at the news.
On Saturday, police detained the owners of two businesses in the building along with two engineers who had been involved in issuing building permits.
Anger at the collapse has sparked days of protests and clashes, with police on Saturday using teargas, water cannon and rubber bullets on demonstrators who burned cars.
Rescuers continued to pull survivors out of the rubble on Sunday, but hopes are beginning to fade for most of the 900 people still counted as missing.
Four people were pulled alive from the wreckage of Rana Plaza four days after the country's worst-ever industrial accident.
Rescuers worked frantically through the morning to release several others who fire service deputy director Mizanur Rahman said were trapped under the mound of broken concrete and metal.
"The chances of finding people alive are dimming, so we have to step up our rescue operation to save any valuable life we can," said Major General Chowdhury Hassan Sohrawardi, co-ordinator of the operation at the site.
About 2,500 people have been rescued from the remains of the building in the commercial suburb of Savar, about 20 miles from the capital, Dhaka.
Officials said the eight-storey block had been built on spongy ground without the correct permits, and more than 3,000 workers – mainly young women – had been sent in on Wednesday morning despite warnings that it was structurally unsafe.
In London, demonstrators gathered outside Primark's flagship store in Oxford Street. A petition has been launched calling for Primark and other brands, including Matalan and Mango, which used the Savar businesses, to compensate the families of workers killed or injured.
Murray Worthy, from the campaign group War on Want, said it was not calling for a boycott that might cost badly needed jobs in the impoverished Asian country: "We're here to send a message to Primark that the deaths in Bangladesh were not an accident – they were entirely preventable deaths. If Primark had taken its responsibility to those workers seriously, no one need have died."