According to Indian intelligence sources, the Ludhiana blast that killed one and injured many, was carried out by two Khalistani supporters—one based in Pakistan and the other in Germany.

Gangster Harvinder Singh Sandhu, also known as Rinda Sandhu, is reportedly under the protection of Pakistani spy agency Inter-Services Intelligence (ISI), and various terror groups. Sandhu is associated with Babbar Khalsa International chief Wadhawa Singh, who is based in Lahore in Pakistan.

The ISI is using Sandhu and the Germany-based Jaswinder Singh Multani to carry out terror attacks in Punjab, according to a report in The Hindustan Times.

Sandhu, who is about 35 years old, is suspected to be in Pakistan after acquiring an Indian passport on a fake identity. He is also involved in large scale cross border smuggling of drugs and weapons.

A known gangster, he is wanted in Punjab, Maharashtra, Chandigarh, Haryana and West Bengal in over 30 criminal cases.

Sandhu is wanted in at least 30 criminal cases–10 murders, 6 cases of attempt to murder, 7 cases of dacoities and snatching besides abductions, extortions and cases under the Arms Act and NDPS Act.

He was arrested for the first time after he killed a man in 2008 over personal enmity in Tarn Taran. In October 2014, he was released on bail from the Nabha jail. He also killed a granthi and disposed of his body in a canal in Gurdaspur in 2016 to avenge the killing of his brother. He killed two other men in Nanded and Wazirabad in Maharashtra.

In 2017, Sandhu escaped from a hotel but the police arrested his wife Harpreet Kaur and another couple. Sandhu appeared in an interview on the web news channel Pro Punjab on June 24, 2021.