The brother of Vegas shooter Stephen Paddock has been arrested for child porn … TMZ has learned.

Bruce Paddock was taken into custody moments ago in North Hollywood, CA at an assisted living home.

Law enforcement sources tell us … cops were tipped that there was child porn on his computer and they got a search warrant. Our sources say the investigation began before his brother, Stephen, shot up the Vegas music festival earlier this month.

Our sources say before the shooting cops were trying to locate Bruce without success, but after his brother committed his heinous act a tip came in Bruce was living at an assisted living facility.

Cops say they found child porn images on his computer.

The arrest was made by a joint task force that included the FBI and LAPD.

This comes after yet another timeline change in the mystery case that Americans may feel will never be solved. However, this family is a lot stranger than we were led to believe and there’s probably more damning secrets hidden behind the Paddock’s walls.

CNN reports of the latest revelations in the seemingly ever-evolving timeline:

Las Vegas authorities have revised the timeline of the mass shooting, saying Stephen Paddock shot a hotel security guard around the time he began firing on the crowd, not six minutes earlier.

Speaking at a Friday news conference, Clark County Sheriff Joe Lombardo didn’t offer any new information about what motivated Paddock to open fire on a country music festival from the 32nd floor of the Mandalay Bay Resort and Casino, leaving 58 people dead.

He said the number of wounded and injured is now 546, with 45 people still hospitalized, some of them in critical condition.

An autopsy was performed and the medical examiner’s visual inspection found no abnormalities on Paddock’s brain, Lombardo said. The brain has been shipped to another facility for “microscopic evaluation,” he said.

The new timeline means police no longer think there was a six-minute gap between the shooting of the guard and the barrage on the concert crowd.

Lombardo said the sequence of events has changed as more information has been obtained. “This is a very dynamic event,” he said, adding that more new facts may be reported.

Initially, police said security guard Jesus Campos approached Paddock’s room as the October 1 shooting was underway, diverting the gunman’s attention. Paddock then shot Campos through the door and quit firing at concertgoers at the Route 91 Harvest Festival from his hotel room on the 32nd floor, the timeline said.

Lombardo’s timeline from Monday — that Campos was shot at 9:59 p.m. and the shooting on the crowd started six minutes later — raised questions about why police didn’t make it to Paddock’s room sooner to break down the door.

On Friday, Lombardo said Campos arrived near Paddock’s suite at 9:59 p.m., but was not shot then. Police Sgt. Joshua Bitsko told CNN that Paddock had screwed shut the stairwell door to the hallway near his room. The security guard went to an upper floor and came back down to the 32nd floor by another door, the sheriff said.

Paddock shot Campos through the door about 10:05 p.m. and began firing on the crowd around then, Lombardo said.

Lombardo’s latest timeline essentially agrees with one put forth Thursday by MGM Resorts International, owner of Mandalay Bay, which disputed the times earlier provided by police. MGM said Paddock was shooting at concertgoers “at the same time as, or within 40 seconds after,” Campos first reported shots.

Why the confusion about what happened at 9:59 p.m.?

Lombardo said the time came from “human entry” in a security log.

“I still stand by the time of 9:59,” Lombardo said Friday. “It wasn’t inaccurate when I provided it to you. The circumstances associated with it is inaccurate.”

MGM said that time “was derived from a Mandalay Bay report manually created after the fact without the benefit of information we now have. We are now confident that the time stated in this report is not accurate.”

There is more that has yet to be released and more arrests that probably still need to be made, but this arrest of the shooter’s brother, even if unrelated to the killing spree, certainly puts a new wrinkle in the strangest investigation in decades.