Matthew Coleman 'Begged Family For Forgiveness' for Allegedly Killing Kids Over QAnon Conspiracies: Source

In the weeks since Matthew Taylor Coleman was arrested for allegedly killing his two children, he as been held at an undisclosed federal prison — but a Coleman family friend tells PEOPLE that he is seeking forgiveness.

"He has spoken to his family on the phone," a longtime family friend tells PEOPLE. "It's sinking in what happened, and he's devastated. He has begged his family for forgiveness."

The family's life changed forever on August 7, when Coleman and his wife, Abby were packing for a family trip. Authorities allege that Coleman abruptly put his two kids — Kaleo, 2, and Roxy, 10 months — into his van and drove away from their Santa Barbara, Calif., home.

Police say Coleman drove the children into Mexico. Two days later, authorities allege, he took the kids to a ranch, were he killed them with a spearfishing gun and returned to his hotel a few hours later. He was arrested when he attempted to cross the border back into the United States.

According to an FBI criminal complaint which was obtained by PEOPLE, Coleman allegedly told police he was motivated by the QAnon conspiracy theory, which holds the false belief that former president Donald Trump has secretly been battling a cabal of Satan-worshipping pedophiles at the highest levels of political power and influence.

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In the criminal complaint, FBI special agent Jennifer Bannon wrote that Coleman claimed to be "enlightened by QAnon and Illuminati conspiracy theories and was receiving visions and signs revealing that his wife, A.C., possessed serpent DNA and had passed it on to his children."

"M. Coleman stated that he believed his children were going to grow into monsters so he had to kill them," Bannon wrote.

Coleman was indicted on murder charges last month. He is eligible for the death penalty. Coleman is now being held in protective custody. He has not yet entered a plea, and the public defender's office has not returned PEOPLE's calls for comment.

For now, Coleman's family and friends are still reeling from the sudden violence, and may not yet be ready to accept his apology

"I think there's compassion there," says the longtime family friend, "but forgiveness is going to take some time. What he did is just so horrific. It's going to take a lot of time for everyone to wrap their heads around it."