The 27-year-old was stalked by someone on Twitter who had sent her 18,888 tweets since November, 2012, reported Sun Online.
The stalker believes that he has some kind of relationship with the Disney actress.
His tweet read, "I'll never lose you baby even in 20 years till infinity you'll always be my best friend."
The suspected tweeter is said to have then shown up at Tisdale's pad, although it's not clear whether the actress was there.
A suspect has reportedly been identified and cops are on a look out to determine whether the stalker poses a serious risk to the star.