A 72-year-old woman was seriously injured when a sophisticated parcel bomb left in front of her house exploded as she tried to open it at a village in Perambalur district, police said today.

Muthammal had seen the parcel left in front of her house as she returned from her farm and attempted to open it when the bomb went off last night in Neykuppam.

The woman had been hospitalised in a serious condition.

Police said District Superintendent of Police Sonal Chandra visited the spot and they were investigating the incident, including the motive.

Bomb experts, who visited the spot, said the explosive device was so sophisticated that it would go off the moment someone touched it after activation.

Initial investigation revealed that two bike-borne persons had left the parcel.