BOSTON (AP) — The man identified by law enforcement as the shooter who killed two Brown University students and an MIT professor had been planning the attack for months and left behind videos in which he confessed to the murders, according to information released Tuesday by the U.S. Department of Justice.

Claudio Neves Valente, 48, a former Brown student and Portuguese national, was found dead in a New Hampshire storage facility after he killed two students and wounded nine others in an engineering building on Dec. 13. Two days later, he killed MIT professor Nuno F.G. Loureiro in his home in the Boston suburb of Brookline.

Justice Department officials said Tuesday that during the search of the storage facility where Neves Valente’s body was found on Dec. 18, the FBI recovered an electronic device containing a series of short videos made by Neves Valente after the shootings.

In the recordings, the shooter admits in Portuguese that he had been “planning the Brown University shooting for a long time,” according to a press release. In a transcript provided by the Justice Department, he said he had been working out details for at least six semesters. He did not provide a motive for targeting Brown or the MIT professor, with whom he attended school in Portugal decades ago.

He said he felt he had nothing to apologize for. He also complained in the videos about injuring his eye in the shootings.

“I’m not going to apologize because during my lifetime no one sincerely apologized to me,” he said.

Neves Valente said his “only objective was to leave more or less” on his “own terms” and to ensure he “wouldn’t be the one who ended up suffering the most from all this.”

“No, that cannot happen. So if you don’t like it, tough luck,” he said. Neves Valente called his execution of the murders "a little incompetent."

“But at least something was done,” he said.

In the recording, he said he’d had the storage space where his body was found for about three years. Neves Valente mentioned his confrontation with the witness at Brown University that ultimately led to his identification days later.

According to police, a witness had several encounters with Neves Valente before the attack at Brown. As police posted images of the person of interest, the witness began posting on the social media forum Reddit that he recognized the person and theorized that police should look into “possibly a rental” gray Nissan. Reddit users urged him to inform the FBI, and the witness said he did.

Up until that point, the police affidavit says officials had not connected a vehicle to the possible shooter.

“I actually was confronted,” Neves Valente said about the shooting at Brown, adding that the witness had seen his license plate.

“I honestly never thought it would take them so long to find me," he said.

He said he had no hatred or love for the United States, where he first arrived around 25 years ago to study physics at Brown's graduate program before leaving in the spring of 2001.

Neves Valente had studied at Brown on a student visa. He eventually obtained legal permanent residence status in September 2017. His last known residence was in Miami.

“It’s the same thing with Portugal, and most of the places where I have been," he said, adding later that “I’ve been here without caring for a very long time now.”