One member of a right wing Hindu group linked to Malegaon blast accused sadhvi Pragya Singh Thakur was killed and another critically injured tonight when an explosive kept in a scooter went off on a busy street in the heart of Margao town, 30 kms from here.

Melgunda Patil, who was one of the two persons injured in the blast, succumbed to his injuries at Goa Medical College.

Police said the blast, triggered at around 9.30 pm, also gutted three vehicles.

The scooter, which contained the explosive, was parked behind Grace Church located in the heart of the town.

Yogesh Naik, another member of Sanathan Sanstha, the right wing Hindu outfit linked to Pragya Singh, is still critical at the hospital, police sources said.

A red alert was declared across Goa after the incident, Superintendent of Police Atmaram Deshpande said.

Margao town, the south Goa district headquarters, is the assembly constituency of Goa Chief Minister Digamber Kamat.

Police have also found a bag containing electric circuit about 20 kms from the blast site in Margao.

Nishad Bakhle, the owner of the Eterno scooter in which the explosive was kept, has also been traced at the Sanatan Saunstha office at Ramnathi in Ponda town 25 kms from here which was raided following the blast, police sources said.

"We are not suspecting anyone at this moment but are not leaving anything to chance," a senior police officer said.

The bag which also contained a watch besides an electric circuit was found at Sancoale village about 20 kms from the scene of the exlosion which took place when a crowd had gathered to witness Narakasura effigy competition held before Diwali in Goa, Superintendent of Police (South) Allan D'Sa said.