A new report from ABC News Wednesday indicates that Stephen Paddock, the alleged Las Vegas shooter, was “descending into madness” in his last few months.

ABC reports that Paddock’s “mental state was deteriorating before the shooting,” while he underwent “significant weight loss, an increasingly slovenly physical appearance and an obsession with his girlfriend’s ex-husband.”

The Islamic State has repeatedly claimed responsibility for the shooting, however, there is no evidence to suggest that this is the case so far.

Paddock carried out the worst mass shooting in modern American history at a country music concert Sunday, killing over 50 people and injuring around 500 more. (RELATED: Trump Speaks In Las Vegas: ‘We Will Overcome Together As Americans’)

His girlfriend, Marilou Danley, was out of the country during the attack. She has returned to the United States and was questioned by the FBI Wednesday about her relalionship with Paddock. (RELATED: BREAKING: Las Vegas Shooter’s Girlfriend Currently Talking To FBI)

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