Rihanna's house was broken into again this week -- the second time someone unlawfully entered this year. Police responded to RiRi's Hollywood Hills home late Tuesday night after an alarm went off around 10:30 PM PT. According to KCBS ... neighbors told police they saw the suspects fleeing in a silver vehicle after the alarm was triggered.
It's unclear if anything was taken from inside -- police say it also doesn't appear that Rihanna was home at the time of the incident. This is the second break-in and third time police have responded to Rihanna's home in force this year -- all over a 4-month time span.
Her house was burglarized in May, when a man had spent the night. He allegedly told cops he was waiting to have sex with the singer. The suspect was charged with felony stalking and burglary shortly after.
And, you'll recall ... cops swarmed Rihanna's house just last month after her alarm was accidentally triggered. It was a massive presence then ... just like it was Tuesday.
Looks like her alarm system got it right this time around.