Top ULFA leader Prabal Neog has confessed that the outfit's commander-in-chief, Paresh Baruah, was the mastermind behind the killing of over 70 Hindi-speaking people in Assam early this year.

In his confessions before the security forces, Neog, the dreaded commander of the ULFA strike force 28 battalion that operates in upper Assam, claimed that he had not carried out any 'operation' on his own but had only followed the orders and instructions of Baruah, with whom he was in close touch, official sources said on Thursday.

Most of the killings of the Hindi-speaking people were carried out in upper Assam.

The ULFA leader, arrested on September 17 in Tezpur, also claimed that 'internal differences' among the outfit's leaders were plaguing it.

He said he had no information about the outfit's 709 battalion, which was responsible for the kidnapping of PC Ram, FCI's northeast regional director.

The sources said that police and security forces were perplexed over the fact that Neog was not carrying any mobile or satellite phone (normally owned by leaders like him) through which he could have got the orders from Baruah.

The police were finding it hard to believe Neog's claim that he was maintaining contact with the top leaders through PCOs, the sources said.