Bruce Paddock, a brother of the Las Vegas gunman, was reportedly arrested Wednesday on suspicion of possessing child pornography. Police sources told media that the child pornography investigation into Bruce Paddock predates his brother’s shooting. The FBI, which is investigating the Las Vegas massacre, declined to comment on the arrest.

One of the brothers of Las Vegas shooter Stephen Paddock was reportedly arrested Wednesday morning on suspicion of possessing child pornography.

Bruce Paddock, 58, was detained by authorities in the Los Angeles neighborhood of North Hollywood, The Los Angeles Times reported.

Los Angeles County Superior Court documents filed on Tuesday show 20 criminal charges against Paddock, according to the Times. All the charges reportedly relate to possession of child pornography or the sexual exploitation of a child.

A felony complaint for an arrest warrant also obtained by the newspaper showed that Paddock allegedly possessed more than 600 images of child or youth pornography, at least 10 of which featured a child younger than 12.

The child pornography investigation into Bruce Paddock predates the Las Vegas shooting and the two incidents are not connected, Los Angeles Police Department spokesman Josh Rubenstein told the Times. Stephen Paddock opened fire on a crowd of concertgoers from his suite on the 32nd floor of the Mandalay Bay Resort and Casino on October 1, killing 58 and injuring hundreds.

Bruce Paddock has only rarely granted media interviews following the shooting, unlike his other brother Eric Paddock, who has spoken to news outlets frequently. Neither are considered suspects in the Las Vegas shooting.

Eric told The Washington Post that Stephen had been largely estranged from Bruce, because Bruce used to beat Stephen up when they were children. Eric said Stephen had also been estranged from another older brother, Patrick.

Bruce told NBC News earlier this month that the FBI had interviewed him about his brother Stephen twice, and that he suspected Stephen had financial difficulties that may have motivated him to carry out the massacre.

An FBI spokeswoman in Las Vegas declined to comment to media outlets about the arrest.