Angela knows too much and it's gotten her into trouble. After learning some information about a local crime spree, the high school student mysteriously disappeared.

On July 10, young adults between the ages of 12 and 18 will try to find her at the annual Troy Public Library lock-in.

The lock-in will be from 7-9 p.m. and for those two hours, the participants will not be allowed to leave.

This is the fourth time the library has hosted a mystery. This year's theme is "Murder in the Islands" and will have a Hawaiian theme.

Teresa Colvin, the children's librarian, said she has had up to 40 teens attend before.

"They always have a lot of fun with it," she said.

This year, participants will be able to visit Angela's locker and witness the interrogation of suspects at the police office. The person who solves the mystery will receive $20 from the Friends of the Library. If a group solves the crime, the members will have to split the cash.

"There are a lot of twists and turns and side stories," Colvin said of the case. "But I figured it out and if I can figure it out, they can figure it out."

There will also be a limbo contest during the lock-in. The winner of the contest receives the new Harry Potter book "The Order of the Phoenix."

Colvin said the Teen Board and members of Baptist Campus Ministries, who are co-sponsoring the event, will be at the lock-in to play mystery roles and ensure a generally good time.

Colvin said she will only take 50 kids. To pre-register for the evening, call the library at 566-1314, but Colvin said pre-registration is not necessary.