OMAHA, Neb. (AP) — Omaha police have begun an internal investigation to determine the reason it took a year to arrest three teenagers accused of sexual assault.

Officer Michael Pecha (PEH’-kuh) confirmed Thursday that police plan to look into the situation. No further details have been released.

An 18-year-old student says she was sexually assaulted at a party in an Omaha apartment and filed a police report Feb. 16, 2014. The three teens accused of being involved weren’t arrested until this year.

Javohn Templeman and Nicholas Bregg, both 19 years old, are charged with first-degree sexual assault. And 18-year-old Jalyia Templeman is charged with felony invasion of privacy.

Preliminary hearings for Javohn and Jalyia Templeman are scheduled for Friday. Bregg will appear in court Feb. 23.