Investigators said the grenade, which landed near a coffee shop, failed to explode.
Market watchmen told probers they heard a dull thud at the second floor of the public market. At first, they said they thought someone hurled a stone into the building from the roadside.
Responding members of the 6th Explosives and Ordnance Detachment managed to promptly deactivate the explosive.
Police said suspected extortionists could have perpetrated the failed bombing attempt to intimidate owners of vending stalls at the public market and, subsequently, force them to shell out protection money. — John Unson