SFPD officer details surreal moment he ID’d CEO murder suspect Luigi Mangione

San Francisco police Sgt. Michael Horan had just cracked open a new missing persons case when updates from a crime 2,500 miles away began flooding the country’s news feeds. 

It was the morning of Dec. 5, and New York officials had released the first photos of an unidentified suspect wanted in the brazen, fatal shooting of UnitedHealthcare CEO Brian Thompson a day earlier.

The suspect’s partially exposed face continued to dominate news cycles as Horan began poring over the Instagram account of the subject in his own missing persons case: a young Ivy League graduate, Luigi Mangione.

“There were a couple of these photos where he’s smiling at just the right angle, and it just kind of dawned on me,” Horan said. “Like, oh, my God. That smile looks exactly like the guy in the surveillance photos.” 

Horan on Wednesday was named officer of the month in December for his role in connecting Mangione to the New York slaying, four days before his name became public following his Dec. 9 arrest at a Pennsylvania McDonald’s. 

The Chronicle in December reported on San Francisco Police’s identification of Mangione, and how local investigators passed the information along to the FBI. But the details of the ID, and the names of the individual officers involved in the local case, have not previously been made public. 

Mangione, 26, now faces a host of federal and state charges, including first-degree murder. He has pleaded not guilty. 

In a Wednesday interview, Horan and fellow investigators with the department’s special victims unit described the first, surreal moments they tied Mangione to the New York case, and the improbable odds of reviewing that missing persons file on Dec. 5.

Mangione’s mother, Kathleen Mangione, had reported her son missing to San Francisco police on Nov. 18, and said she hadn’t spoken to him since July. The mother reported that Mangione had been working at a car listings website that had an office in San Francisco, but that the location was permanently closed and the main number was disconnected. 

Sgt. Joe Siragusa, the first investigator assigned to the case, said he had a long conversation with Kathleen Mangione, who put him in contact with one of her son’s good friends, who he grew up with in Baltimore. The friend told Siragusa that Mangione was supposed to attend his wedding that summer, but that he had failed to show up. 

“Luigi sent him a really detailed message, about how life had gotten tough and nobody understood him,” Siragusa said. 

The friend also filled Siragusa in on what is now widely known biographical information about Mangione: He was extremely intelligent, active and athletic and had recently been living in Hawaii. The friend also told Siragusa that Mangione had been suffering from back pains that had significantly disrupted his life, both physically and mentally.

Still, Siragusa said the friend didn’t believe it was likely that Mangione was suicidal or would become the victim of a crime. The friend described Mangione’s mother as somewhat overbearing and said there had been some division between the young man and the rest of his family. 

“Our mindset at that time is like, ‘Maybe Luigi didn’t want to be found,’” Siragusa said. “Which is his right, so to speak.” 

Police found little physical evidence of Mangione in San Francisco. The number Mangione’s mother had provided had been dead since July, though there was some minor, non-suspicious activity on his bank account in the city in August. 

Siragusa said Mangione’s family continued to call the department for updates on the case, and on Dec. 5, he had asked his partner, Horan, to take a second look. 

After conferring with Siragusa and other officers at the station, the investigators decided that the likeness to the murder suspect was strong enough to pass the tip onto the local FBI, who forwarded the information along to New York officials. 

Before police could fully vet the tip, officials said, Mangione was separately spotted having breakfast at McDonald’s.

Special Investigations inspector Sgt. Anthony Flores said the department hasn’t received any updates from their New York counterparts recently, but that he wouldn’t be surprised if Horan and Siragusa one day get called to testify in Mangione’s trial, given their investigation into his whereabouts and recent history. 

“I’m proud of the team,” he said. “The team does a great job with the resources that we have.”

Earlier on the morning of Dec. 5, even before laying eyes on Mangione’s missing-persons report, Horan recalled noting the distinct smile of the still-unidentified New York murder suspect, the kind of smile that would be easy to spot.

“I remember thinking to myself, ‘Well, somebody’s going to recognize that guy,’” Horan said. “Someone’s going to have him ID’d by the end of the day.” 

Reach Megan Cassidy: megan.cassidy@sfchronicle.com