Stephen Paddock had hundreds of images of child pornography in his possession when he carried out the Las Vegas mass shooting on Oct. 1, according to a report released by the Las Vegas Metropolitan Police Department on Friday.

The child porn was found on a Dell laptop computer in the Mandalay Bay hotel room from where Paddock slaughtered 58 people attending a Jason Aldean concert below. The report says that “several hundred images of child pornography were located on the computer’s hard drive. The investigation into the source of these images is ongoing.”

Paddock’s younger brother, Bruce Paddock, was arrested in late October after police found child pornography on his computer at home.

Clark County Sheriff Joe Lombardo said the investigation has yet to reveal a motive for the mass shooting, which was the deadliest in American history.

Lombardo said Stephen Paddock’s girlfriend, Marilou Danley, is not expected to be charged in connection with the shooting. Lombardo did note that the FBI is looking into one other “individual of federal interest” but offered no further details.