Trans killer Robert Dorgan had a permit to carry a firearm, and used a high-powered handgun to murder his son and ex-wife at a high school hockey game in Rhode Island on Monday.

The 56-year-old dad of six, who also went by Roberta, obtained a concealed carry permit in Florida, but it did not cover Rhode Island, Pawtucket Police Chief Tina Goncalves said during a news conference this week.

Dorgan used a Glock 29 10mm purchased in Jacksonville in September 2021 and a .357 Sig-caliber Sig Sauer P226 bought in July 2019 in West Warwick, R.I., to slaughter ex-wife Rhonda Dorgan, 52, and their son, Aidan, 23, at Lynch Arena in Pawtucket at around 2:30 p.m. on Monday.

The 10mm round — made mainstream in the show “Miami Vice” — is nearly twice as powerful as the 9mm carried by many police departments and the the US military.

It is considered big enough for hunters to use on bears or deer.

The trans gunman also critically wounded Rhonda’s parents, Gerald and Linda Dorgan, as well as family friend Thomas Geruso, before taking his own life.

State law “requires a Rhode Island state permit to carry, with one exception,” attorney general’s office spokesman Tim Rondeau said when asked whether Dorgan’s Florida permit would have been valid in Rhode Island, the Providence Journal reported.

“That exception is if the person carrying or transporting the firearm is merely passing through the state on the way to somewhere else,” Rhondeau said.

“An out of state permit is not valid in Rhode Island,” Glenn Valentine, vice president of the Rhode Island Firearms Owners League, told the Providence Journal.

Dorgan was living in Jacksonville several years ago, but Florida removed its permitting requirement in July 2023, although permits issued prior to that “were valid for seven years,” Valentine added.

“Most folks outside of Rhode Island don’t pursue a permit [here] given that the process is beyond what [most of] the rest of the country requires,” he said.

Dorgan would have had to apply for a license in his town of residence or with the attorney general’s office, Rondeau said.

It isn’t clear if he ever did so.

The minority Republicans in Rhode Island have introduced bills that would grant concealed-carry privileges to gun owners from other states that provide reciprocal privileges to gun owners in the state – subject to action by the attorney general.

Follow The Post’s latest coverage on the Rhode Island high school hockey shooting

Two separate bills were introduced in the state’s Senate and House, sponsored by Republicans, but neither made it out of a legislative committee last year.

A Senate version was reintroduced this year.

Authorities are still building a picture of Dorgan, who became the fourth high-profile transgender mass shooter in North America in recent years.

Earlier this month, Canadian Jesse Van Rootselaar, 18, who identified as trans, murdered his mother and stepbrother before killing six others at his former school in British Columbia.

Dorgan had undergone male-to-female gender reassignment in recent years, after a troubled life that saw him booted out of the Marine Corps after less than three months in 1988.

He was charged with simple assault and battery in 1989, but the case was dismissed.

Rhonda claimed that Rhonda’s father had ordered him to leave the house after he underwent surgery in 2020, according to a police report.

But his Nazi tattoos and description of his politics as “to the right of Hitler,” on X, suggest a deeply troubled individual who spiraled in recent years.