The New Jersey man charged with torching his own house hours before his murdered brother’s mansion burned to the ground — with his wife, son and daughter dead inside — says he is totally innocent.

“He fully expects to be vindicated,” said Robert Honecker, the lawyer for Paul Caneiro, on Friday.

Suspicion first fell on Caneiro, 51, when both brothers’ Jersey homes went up in flames Tuesday.

At 5 a.m., Paul doused his Ocean County home with gasoline and set it ablaze, prosecutors allege. His wife and two daughters escaped the flames without injury.

“Must have been a gas leak,” Paul told a neighbor, according to the Asbury Park Press.

Then, that afternoon, the Colts Neck mansion belonging to Paul’s brother Keith, 50, began burning.

Keith was found dead on the lawn of multiple gunshot wounds.

Dead inside the home were his wife, Jennifer, 45, and their son James, 11, and daughter Sophia, 8. Medical examiners have not yet determined their causes of death.

The brothers were in business together. Paul helped run Keith’s tech company and pest control businesses, which both operated out of an office in Asbury Park.

Forensic investigations are underway at both charred homes, officials said Friday.