There’s more information in the embedded press briefing by police, but for a quick link to start it off
CNN coverage puts it part way down the article:
“According to L.A. County Sheriff Alex Villanueva, "there were two calls that came in, almost at the same time."
"One that described the kids as the aggressors. The other one described the homeless person as the aggressor," he said in a
news conference on Wednesday.“
As far as the rifle piece, I’m not sure it was necessary. But, swung with ill intent, a skateboard can be a deadly weapon, at least the ones I rode many years ago had substantial metal “trucks” underneath that could crack a skull. More so if it’s a group attack.