Luigi Mangione was arrested following the death of UnitedHealthcare CEO Brian Thompson

Suspected shooter Luigi Mangione was reported missing by his family in November and CCTV images of him ignited suspicions, law enforcement sources have said.

Mangione, 26, remains in police custody after being arrested and charged with the murder of UnitedHealthcare CEO Brian Thompson, 50.

Thompson was walking to an insurance conference in New York City on December 4 when he was shot from behind outside of the Hilton Hotel.

Following the shooting, video footage of the incident began to circulate on social media and police called on the public for more information about the identity of the alleged killer.

This included revealing images of an individual they wished to speak to in connection with the crime.

Luigi Mangione has been charged with the murder of the UnitedHealthcare CEO (Jeff Swensen/Getty Images)

Cops finally caught up with the suspect as Mangione was sitting at a table in the rear of a McDonald’s in Altoona, Pennsylvania, wearing a blue medical mask and looking at a laptop, documents state.

However, the day prior, it’s been reported that Mangione’s mother spoke to the FBI and the police about a possible connection between the person police wanted to speak to and her son.

This came after the San Francisco police contacted the FBI about the identity of the man in that photo. The tip from them came on December 6 and police contacted Mangione’s mother two days later, law enforcement sources have said.

After speaking with his mother, Mangione was arrested at the McDonald’s restaurant, officials have said.

According to law enforcement sources, as per the New York Post, she had told them her son bore a resemblance to the suspect.

She had reported him missing to San Francisco police the month prior on November 18 and claimed she had not spoken to her son since July 1 and was not aware of his whereabouts.

Republican Maryland state legislator Nino Mangione issued the family’s statement in a post on social media.

A missing person poster of Mangione (NBC News/Police)

It read: “Our family is shocked and devastated by Luigi’s arrest

“We offer our prayers to the family of Brian Thompson and we ask people to pray for all involved.”

On Tuesday (December 10), the computer science graduate – who is understood to have come from a wealthy family in a Maryland community, and was raised in Towson, outside of Baltimore – entered a plea of not guilty.

On the same day, his defense attorney Tom Dickey, of Pennsylvania, spoke to the press on behalf of his client.

He said: “If the government charges a person with a crime they have to prove that, and they have to have some evidence.”