UnitedHealthcare CEO Brian Thompson’s alleged assassin Luigi Mangione was “irritated” before his public outburst because there was no lawyer to support him as law enforcement officials dragged him inside a Pennsylvania courthouse this week.

Mangione hadn’t vented his frustration to anyone after he was nabbed from an Altoona, Pa., McDonald’s Monday morning, according to his lawyer, Thomas Dickey.

During his outburst, Mangione yelled at the group of reporters that had gathered outside as cops hurried him into the Blair County Courthouse in Hollidaysburg, Pa.

“He’s irritated, agitated about what’s happening to him and what he’s being accused of,” Dickey told CNN Wednesday. “He never had any legal representation until he walked into that building yesterday.”

“It’s completely out of touch and an insult to the intelligence of the American people and the lived experience!” the 26-year-old shouted.

Dickey took credit for being the one to work with Mangione inside the courthouse and calm him down before his frustrations got him into more trouble.

“I talked to him … look at the difference between when he went in and when he came out … now he has a spokesperson and someone that’s going to fight for him,” the Pennsylvania-based lawyer said.

During his appearance on CNN’s “Erin Burnett Out Front,” Dickey shared his skepticism about the NYPD’s evidence gathering and said he wants to view the fingerprint and gun ballistic evidence himself as the procedures have known faults.

“Those two sciences, in and of themselves, have come under some criticism in the past, relative to their credibility, their truthfulness, their accuracy, however you want to do it,” Dickey said.

Mangione’s defense team wants to view the evidence and know how the investigators collected the samples and results before having its own “experts” look at the data before it “challenge[s] its admissibility and challenge[s] the accuracy of those results.”

On Wednesday, NYPD Commissioner Jessica Tisch revealed the bullet casings found at the scene of Thompson’s fatal shooting in Midtown Manhattan matched the gun Mangione was carrying at the time of his arrest.

“First, we got the gun in question back from Pennsylvania. It’s now at the NYPD crime lab,” Tisch said, giving a brief update on the investigation Wednesday.

“We were able to match that gun to the three shell casings that we found in Midtown at the scene of the homicide,” Tisch told reporters during an unrelated press conference on Staten Island.

Mangione was charged in Pennsylvania for a slew of charges including murder and gun possession.

He has pleaded not guilty to the charges and Dickey had asked the court for Mangione to be let out on bail, which was denied at an extradition hearing on Tuesday.