The arrest yesterday is being seen as the state government's move to put pressure on GJM, which is demanding a separate Gorkhaland in the aftermath of the announcement on Telangana.
Thapa was detained last evening, hours after Gurung said in Kalimpong that there would be no negotiation on the Gorkhaland demand and GJM would not hold talks with the state government on it, but only with the Centre.
As the news of his arrest spread, GJM supporters and workers gathered outside Kurseong station and shouted slogans. A total 51 GJM workers have been arrested since the launch of the indefinite bandh by it on Saturday.
Meanwhile, life continued to be paralysed in Darjeeling Hills for the fourth day due to the indefinite bandh called by GJM.
West Bengal Home Secretary Basudeb Banerjee has reached Siliguri and is scheduled to hold talks with top district officials on the overall situation there.
Shops, markets, educational institutions and private offices remained closed and no vehicle was seen on the roads.
Government offices remained open as per orders but there was no attendance.
Patrolling is on by CRPF, IRB and Striking Force personnel besides the district police.
