Los Angeles is still reeling from the terrifying shooting at Rihanna's home Sunday ... and we have video of authorities racing to get to the bottom of it.

Yellow caution tape closed off the block today as an officer at the crime scene told us the investigation is still ongoing.

As we reported ... a 35-year-old woman named Ivanna Lisette Ortiz has been booked for attempted murder after allegedly firing multiple rounds into Rihanna's home from her car.

Rihanna was home at the time but it's unclear whether A$AP Rocky or their children were with her.

Disturbingly, Ortiz seems to have been posting online about Rihanna for some time, although there's no known link between the two.

And a Facebook message from her account on February 23 reads, "@badgalriri Are you there? Cause I was waiting for your AIDS 5-head self to say something to me directly instead of sneaking around like you talking to me where I'm not at."

In videos uploaded to YouTube in January, Ortiz appears to clutch a 'Praying Woman's Journal' while ranting incoherently about Rihanna's death and other topics.

Ortiz is currently in custody with bail set at $10,225,000.