Karo, North Sumatra. The North Sumatra Police announced on Monday that they have launched a murder investigation and arrested two suspects after a local journalist, his wife, son, and grandchild were found dead inside their burned house in Karo regency on June 27.

Provincial Police Chief Agung Setya Imam Effendi said investigators had reviewed security camera footage from the area and identified the two suspects as having doused the house walls with gasoline.

"We arrested the arsonists today and will continue to identify other perpetrators in this case,” Agung said. "We are working to determine the motive for this crime.”

Agung added that his team needs more time to identify additional perpetrators and the mastermind behind the arson, which killed TV journalist Sempurna Pasaribu (47), his wife Efrida (48), their 12-year-old son, and their 3-year-old grandchild.

Police reported that one of the suspected arsonists was shot because he resisted arrest.

The North Sumatra Journalist Safety Committee had earlier released findings from its investigation, suggesting that Sempurna was killed due to his journalistic work on gambling.