Gilda Joyce: The Ladies of the Lake by Jennifer Allison

Miss Underhill frowned at Gilda as if she were suddenly speaking a foreign language. "What?"
"You said her ghost rises out of the water screaming. Then what happens?"
"I don't think I want to find out."
Gilda's mind raced with questions. Was Our Lady of Sorrows truly haunted, or was Miss Underhill simply trying to scare her? What were the circumstances surrounding Dolores Lambert's death by drowning?
Gilda had just made up her mind; she wanted to attend Our Lady of Sorrows. (25-26)

Gilda Joyce has won a scholarship to the prestigious all girls Catholic high school in Bloomfield Hills, Michigan. While initially skeptical about attending, she's convinced to attend when she hears about a drowning "accident" that occurred three years ago. She's anxious to prove her worth as a paranormal investigator, but after her first day at school, she realizes that not everyone is as excited as Gilda to investigate a tragedy. When the girl's ghost starts haunting some of the students and the school, will this convince Gilda to halt her investigation? Gilda Joyce: The Ladies of the Lake by Jennifer Allison is actually the second in a trilogy of books detailing Gilda's mysteries.

AMY