The 24-year-old woman known only as Xi said she works in Singapore, and had not changed the address on her identity card after leaving the house almost 10 years ago.

“I apologise for involving the residents of this house. It was my fault for not changing my address, which endangered these innocent people.

“I thought they were just making threats. I did not expect that the situation would escalate to this,” she said at a press conference here today.

Xi said she borrowed money from a Singapore-based loan service she had found through a Facebook advertisement and warned the public to avoid such services.

One of the tenants, known as Hong, was in the living room when he noticed a fire in the porch area at 1.20am on April 13.

Hong, 66, alerted the other male tenant, known as Tang, 40, who then called their neighbour for help in extinguishing the fire.

The fire left burn marks on the porch and the interior ceiling, and cracked a glass panel at the front of the house.

“It usually takes 10 minutes for us to get out of bed. If we were asleep when it happened, we might have not made it,” Tang said.

DAP MP Lim Lip Eng said he received a complaint from Xi yesterday, after she received a video recording of the act and a message warning her that failure to settle her debts would result in daily harassment.

The eight-second video showed the attacker leaving a note at the front gate of a house before lighting up an object and hurling it into the house compound.

The suspect then rushed into a vehicle and fled the scene.

Lim said this was not a mere threat, but a crime that endangered public safety, and urged police to take swift and decisive action.

Tang said authorities collected evidence and recorded their statements yesterday.

He said some neighbours also noticed the perpetrator circling the house three times in a silver car before committing the act.