(CNN) The man who attempted to rob a Manila casino, leading to the deaths of 37 people, had fallen prey to the gambling industry, his parents told CNN Philippines.
Teodora Carlos, the mother of the gunman, identified by police as 42-year-old Philippines national Jessie Carlos, said that he was a "good person" who changed when he started frequenting casinos.
"My son was just a victim... he fell victim to the casinos," she said, according to a translation provided by CNN Philippines.
She said that the family was struggling to come to terms with what Carlos had done.
"I still don't want to accept that it was my son, because my son was a good person."
Gunman attacks Manila casino resort: How it unfolded
Manila police had earlier revealed that Carlos was tens of thousands of dollars in debt and had a gambling problem.
He had been banned from all casinos by the Philippine Amusement and Gaming Corporation at the request of his family, which police are looking at as a motive for his attack at the Resort World Manila casino in the early hours of Friday.
"This could have probably triggered him, which is why he was so angry at the casinos," National Capital Region Police Office chief Oscar Albayalde said at a press conference Sunday.
"He knew that he couldn't just go into a casino to gamble because his picture would be posted there and he wouldn't be allowed inside."
The suspect was a former tax specialist at the Department of Finance, Albayalde said. He was fired in 2014 due to false declarations and nondisclosure of assets and had racked up bank debts of 4 million pesos ($81,000).
Albayalde said the incident is now a "closed case" with regards to the identity of the perpetrator.
ISIS had claimed responsibility for the attack Friday, but officials have repeatedly denied it was terror-related. US President Donald Trump mislabeled the incident a "terrorist attack" on Thursday.
Carlos entered the Resorts World Manila shortly after midnight Thursday, firing shots from an assault rifle and setting fire to gambling tables.
Most of the victims -- 24 resort guests and 13 employees -- are believed to have died of smoke inhalation.
He ransacked a room and stole gaming chips totaling 113 million pesos ($2.3 million), Philippine National Police Chief Ronald Dela Rosa said. He stuffed the chips in a backpack, which police later recovered, he said.
During the attack, the gunman engaged in a firefight with casino employees, police said.
Carlos was shot and wounded by security guards, and retreated into a hotel room, where he doused a bed with gasoline and shot himself, police said.
He was found dead around 7 a.m. local time, according to a statement from the resort.
CNN Philippines reported he was found in the room, his body burned beyond recognition. It was next to an automatic weapon and a .380-caliber pistol.
Carlos' mother urged others to look to her son's case as a reason to avoid gambling.
"I think what happened to my son shows everyone not to get into gambling so that their families will not be ruined."