A San Diego County man is in police custody after posting graphic videos on YouTube where he appeared to be practicing a mass shooting, police said.

Steven Homoki, 30, was arrested on Thursday on suspicion of possession of an assault weapon, possession of a high capacity magazine and child endangerment, San Diego police said in a statement Friday.

Authorities received a tip about Homoki, of Spring Valley, California, on Monday, concerning videos he posted online. The tipster reportedly said Homoki had "gone off the deep end" and said he had a "plan" in place, according to NBC San Diego.

Steve Andrew Homoki in an undated photo. via NBC San Diego

In the videos, Homoki is seen in a San Diego hotel room with several guns, magazines and bullets. The video, obtained by NBC San Diego, appears to shows Homoki loading the guns, crawling on a bullet-strewn floor, loading guns and pointing the weapons at pedestrians out the window.

In one moment, Homoki pulls the trigger on an unloaded rifle pointed at pedestrians and says, "One down, more to go."

"You drop one mag, you pick up another, right? Then you pick up another. ... Then you drop it, you drop the gun, pick up another gun," Homoki said under his breath on the video, which seems to be recorded from a body camera.

San Diego's Joint Terrorism Task Force began investigating the video after the tip, which it tied to Homoki. Authorities said they obtained a search warrant for his home, where he was arrested Thursday and where they seized several firearms.

"Just three days ago Mr. Homoki was an unknown poster of disturbing videos and is now behind bars, his threats neutralized," San Diego FBI Special-Agent-In-Charge Scott Brunner said in a statement.

San Diego police did not provide provide more details on the child endangerment charge of which Homoki is also accused.