New Delhi, Mar 23 (PTI): Home Minister Rajnath Singh has asked Chief Ministers of Tamil Nadu, Karnataka and Madhya Pradesh to ensure expeditious probe of unresolved terror cases in their respective states, saying arrest of the guilty will be the "best recipe" to prevent similar attacks in future.

In separate letters to O Panneerselvam (Tamil Nadu), Siddaramaiah (Karnataka) and Shivraj Singh Chouhan (Madhya Pradesh), the Home Minister said it was important for all concerned to take terror investigations to their logical conclusion by arresting the accused, having them prosecuted and finally convicted for their crime.

"This is the best recipe to prevent future attacks by the same outfit or individuals. In this regard, I would urge upon you to personally look into the case and ensure that the investigating agency makes all out efforts to achieve a breakthrough," he said.

The Home Minister wrote to Siddaramaiah that one person was killed and three others injured when in an IED blast in Bengaluru on December 28, 2014, noting that no one has been arrested even though the case was under investigation of Karnataka Police.

In his letter to Chouhan, Singh said that five under trial militants of banned terror group SIMI escaped from state's Khandwa jail on October 1, 2013 but even after "a lapse of more than a year", the terrorists have not yet been arrested.

Singh said there are reasons to believe that this group of escaped SIMI terrorists has carried out bomb blasts and other crimes in different parts of the country.

"In fact, this group has emerged as a major security challenge to the country and has managed to successfully to evade arrest by the law enforcement agencies of different states," he wrote.

Referring to the May 1, 2014 blast at Chennai railway station in which one person was killed and 14 others injured, Singh told Panneerselvam that the case was investigated by the CB-CID of Tamil Nadu but no one has been arrested so far for the terror act.

Singh told the three Chief ministers to personally look into the cases and direct the concerned police authorities to make sustained efforts to arrest those who were responsible for the terror acts.

Singh also offered central government's help to the states to take the cases into their logical conclusion.