What Was Found in Luigi Mangione’s Backpack? A Simple Breakdown of the Evidence

The Big Picture

On December 9, 2024, police arrested Luigi Mangione at a McDonald’s in Altoona, Pennsylvania. He is the suspect in the fatal shooting of Brian Thompson, the CEO of UnitedHealthCare. When officers searched Mangione’s black backpack, they found several items that prosecutors say connect him directly to the crime.

What Was Inside the Backpack?

Here is a simple list of the key items police discovered:

• A loaded magazine (the part of a gun that holds bullets) wrapped in a pair of underwear
• A Faraday bag — a special pouch that blocks all cell phone signals — containing:
  • A passport
  • A phone
  • A wallet
• Multiple changes of clothing
• Toiletry items (like toothbrush, soap, etc.)
• A silencer (a device attached to a gun to make it quieter)
• A 3D-printed gun — a firearm made using a 3D printer
• Handwritten pages from a red notebook that prosecutors call a “manifesto” expressing anger toward the healthcare industry

Important Point: The District Attorney’s Office says the 3D-printed gun matches the ballistic evidence (bullet markings) from the Manhattan crime scene where Brian Thompson was shot.

Other Evidence Linking Mangione to the Crime

• DNA and fingerprints belonging to Mangione were found on several items left behind by the shooter near the crime scene in Manhattan.
• Prosecutors shared this information in official court documents.

What Evidence Can Be Used at Trial?

In May 2025, Judge Gregory Carro made a major ruling about what prosecutors can show the jury during the upcoming state trial.

Allowed at Trial:

• The 3D-printed gun
• The red notebook with handwritten entries

Excluded from Trial:

Items found during the initial search at the McDonald’s, including:

• The loaded magazine
• Passport
• Wallet
• Cell phone
• Computer chip

Why were these excluded?
The defense argued that police searched the backpack without a warrant at the time of arrest. The judge agreed, so those items cannot be used as evidence in the state trial.

Summary

• Luigi Mangione was arrested at a McDonald’s in Pennsylvania on December 9, 2024.
• His backpack contained a 3D-printed gun, silencer, loaded magazine, Faraday bag with personal items, clothing, and a red notebook with anti-healthcare writings.
• The gun matches ballistics from the NYC shooting of UnitedHealthCare CEO Brian Thompson.
• Mangione’s DNA and fingerprints were on items left near the crime scene.
• A judge ruled the gun and notebook can be used at trial, but items from the warrantless backpack search cannot.

FAQ

1. What is a 3D-printed gun?

A 3D-printed gun is a firearm made using a 3D printer, which builds objects layer by layer from plastic or metal. These guns can sometimes avoid metal detectors and aren’t always registered.

2. What is a Faraday bag, and why does it matter?

A Faraday bag blocks all wireless signals (like cell service, GPS, Wi-Fi). It’s often used to prevent tracking or remote wiping of a phone. Finding one suggests someone may be trying to hide their digital activity.

3. Why was some evidence thrown out?

The judge ruled that police searched Mangione’s backpack at the McDonald’s without a warrant, which violates the Fourth Amendment (protection against unreasonable searches). So, those items can’t be used in the state trial.

4. Can the excluded evidence be used in a federal trial?

Possibly. This ruling only applies to the state trial. Federal prosecutors may have different rules and could still use that evidence in a separate federal case.

5. What is a “manifesto” in this context?

Here, it refers to handwritten notes expressing strong personal beliefs — in this case, frustration and anger toward the healthcare industry. Prosecutors say it shows motive.