Four members of the same family in the northwestern city of Medellin were hacked to death with a machete, Colombian authorities said Monday.

The Medellin Mayor's Office and the National Police on Monday offered a reward of 40 million pesos ($21,160) for information instrumental in solving the crime.

The multiple murders occurred on Sunday in a house in Comuna 13, a sprawling cluster of slums on the edge of Colombia's second city.

The dead included a 6-year-old girl, her mother and maternal grandparents, police said.

The head of the Medellin Metropolitan Police, Gen. Jose Angel Mendoza, told reporters that inside the house authorities found a "distasteful scene," given that the victims were killed by at least one assailant with a machete.

Among the hypotheses authorities are considering is that the crime could be a case of intrafamily violence. EFE