The police have not been able to make any breakthrough in the probe into Sunday’s attack at a newspaper office here. In the incident three of the paper’s staffers were stabbed to death by masked assailants. Chief Minister Manik Sarkar, accompanied by Director General of Police Sanjay Sinha, visited the office of Dainik Ganadoot on Monday.

Two unidentified assailants knifed the newspaper manager, a proof reader and a driver. The police said two of the victims were also strangled besides being stabbed.

The triple murders have created a sensation and panic in Tripura, even as media organisations, political parties and individuals condemned them. The main opposition party, the Congress, has called a 12-hour general strike here on Tuesday in protest against the “deteriorating law and order situation.”

“We are looking into different angles. We have got some vital clues and expect to make remarkable progress very soon,” a senior police officer said on Monday. He hinted that the attack was carried out by professional killers.

Mr. Sarkar, who earlier directed the police to quickly crack the case, visited the crime scene, consoled the widow and the daughter of the murdered driver and talked with the paper’s editor-cum-proprietor Sushil Choudhury.

Mr. Choudhury had earlier claimed that he was the main target and the assailants mistook his manager to be him. However, he did not say why he thought he was the target.

The ruling CPI (M) has urged the State government to ensure that the investigation get to the bottom of the matter. The Agartala Press Club and working journalist organisations made the same demand. They also sought compensation and government jobs for the bereaved families.

Condemnation and demands poured in from abroad with the International Federation of Journalists (IFJ) expressing serious concern over the incident.