Former W.H. Photographer Reveals Never-Before-Seen Photos of Obama's Anguish After Sandy Hook

Former official White House photographer Pete Souza shot close to two million photographs of then-President Barack Obama during his eight years in office — and they weren’t all cute candids with kids.

In his new book, Obama: An Intimate Portrait, Souza reveals that one of his hardest days on the job was also what he described as “the worst day” of Obama’s presidency: December 14, 2012, when 20 first-grade students and six staff members died in the shooting massacre at Sandy Hook Elementary School in Newtown, Connecticut.

“[The shooting] affected me in a profound way that no other situation in the eight years did. I can feel my eyes tearing up now just talking to you about it,” Souza says in an exclusive interview with PEOPLE. “It certainly affected [President Obama] … He cried on stage one time reliving that, because I think he was reacting not just as a president, but as a parent.”

In his book, Souza presents four photographs capturing the Obama family’s personal response to the tragedy. One photo shows Obama first learning of the deaths from Homeland Security Advisor John Brennan. (Souza explained that all photos that were never before released were published with the Obamas’ permission.)

“The president slumped in reaction against the Oval sofa, visibly deflated,” Souza writes in his book. “I’m sure he was thinking foremost of the parents, imagining the horror of learning that their six-year-old son or daughter had been shot to death by a madman and would never come home.”

Opposite that snapshot, Souza presents a never-before-seen photograph of President Obama hugging daughter Malia in the private residence later that same day as an anguished Michelle Obama looks on. “The president hugged her for a long time,” Souza writes. In the third photograph, Obama hugs the mother of Ben Wheeler, a first-grader who was killed in the shooting.

“I don’t think I’m the best photographer in the world. I’m a competent photographer,” Souza said when asked how he captured such emotionally charged moments. “But I think I was absolutely the right person to be [President Obama’s] photographer… I think he trusted me completely… I was respectful of their privacy. I would make a few pictures in intimate situations and back away when I needed to.”

Barack Obama agrees.

“In addition to his exceptional eye, Pete has a remarkable talent for making himself invisible. In fact, what makes Pete such an extraordinary photographer, I think, is something more than his ability to frame an interesting moment. It’s his capacity to capture the mood, the atmosphere, and the meaning of that moment,” Obama writes in the book’s foreword.

He also describes Souza as “a friend, a confidant, and a brother,” adding that the photographer and his wife, Patti, are so much a part of the Obama family that their wedding was held in the White House Rose Garden.

Two days after the shooting, Souza joined the president for the memorial service in Newtown. But not before catching Obama’s daughter Sasha’s dress rehearsal for her dance recital.

Souza says that Obama prepared his remarks before the memorial service in a classroom in Newtown High School.

“Two teachers had written on the whiteboard: ‘Dear President Obama, the Newtown community is so thankful that you are coming to help us heal. In times of adversity it is reassuring to know that we have a strong leader to help us recover,’ ” Souza recalls in his book. “The president wrote his response on the board: ‘You’re in our thoughts and prayers.’ ”

Beyond his work photographing some of the Obamas’ most iconic and intimate moments, Souza has gained attention for his Instagram presence. He often posts photos from the Obama presidency with captions subtly highlighting the jarring contrast between the Obama and Trump administrations.

“It’s funny that people think I had some grand strategy. I didn’t,” Souza said when asked about his intention behind his posts, which have been celebrated in headlines high-fiving his “shade-throwing” and “Trump trolling.”

“I didn’t even realize what I was doing, to be honest with you,” Souza said. “I had to look up what the term ‘throwing shade’ meant.”

He added: “[Now] I think it’s better not even to talk about it, to just let it speak for itself. Respectful and subtle … People judge it for what it is, which is fine by me.”

Obama: An Intimate Portrait is on sale now.