One person was killed and four persons were injured in two separate incidents of violence in Assam on Sunday.

Bijoy Shankar Hazarika, a surrendered militant of the United Liberation Front of Asom, was seriously injured and his wife Anita Barman was killed when unidentified gunmen fired at them in Ghograpar at Assam's Nalbari district on Sunday afternoon.

The police suspect that personal rivalry may be the motive behind the attack on the surrendered militant. They are trying to ascertain the identity of the assailants.

The couple, along with their son, was traveling on a motor-cycle when the assailants started shooting at them. Anita was killed at the spot and a seriously injured Bijoy was rushed to the Guwahati Medical College Hospital.

In a separate incident, three people were injured in a grenade blast near the Anthgaon flyover, in the heart of Guwahati, on Sunday evening.

The police said that suspected ULFA militants had hurled the grenade at a police-Central Reserve Police Force patrol party and missed the target. The grenade exploded in front of a local hotel, injuring three civilians.