Veteran homicide investigators in New York and Washington, DC, on Monday questioned the way local and federal authorities in Texas handled the death of Supreme Court Justice Antonin Scalia.

“It’s not unreasonable to ask for an autopsy in this case, particularly knowing who he is,” retired Brooklyn homicide Detective Patricia Tufo told The Post.

“He’s not at home. There are no witnesses to his death, and there was no reported explanation for why a pillow is over his head,” Tufo said. “So I think under the circumstances it’s not unreasonable to request an autopsy. Despite the fact that he has pre-existing ailments and the fact that he’s almost 80 years old, you want to be sure that it’s not something other than natural causes.”

Bill Ritchie, a retired deputy chief and former head of criminal investigations for the DC police, said he was dumbstruck when he learned that no autopsy would be performed.

“I took a look at the report and I almost fell out of my chair,” Ritchie told The Post from his home in Maryland.

“I used to be an instructor in the homicide school. Every death investigation you are handling, you consider it a homicide until the investigation proves otherwise,” Ritchie said.

“How do you know that person wasn’t smothered? How do you know it’s not a homicide until you conduct an investigation? You have to do your job. Once you go through that process, you can conclude that this is a naturally occurring death.”

Presidio County Judge Cinderela Guevara said she declared Scalia dead via telephone based on what cops and marshals at the scene told her — that there were no signs of foul play.

“How in the world can that Texas judge, not even seeing the body, say that this is a heart attack?” Ritchie wondered. “A US marshal can’t tell you. You need a medical professional. If this was Joe Blow, you say OK, 79 years of age, health problems, maybe natural causes. But this is a sitting justice of the Supreme Court!”

Guevara also spoke by phone with Scalia’s physician, who told her Scalia had several chronic medical conditions and had gone to the doctor’s last week for a shoulder problem, reports say.

Scalia’s family did not want an autopsy, she added.

With AP