FBI officials have confirmed that they’re now investigating the shooting death of 17-year old Trayvon Martin. According to MSNBC, FBI agents confirmed Monday that were questioning potential witnesses and had begun a “parallel investigation” to see whether the teen’s civil rights were violated. As previously reported, George Zimmerman admitted to shooting the unarmed 17-year-old but claimed it was self-defense.

The FBI is now investigating the gunman’s background to determine if his actions were racially motivated when he killed the teen. Phone records that show Zimmerman made prior 911 calls to police dispatchers that may be used as evidence in the investigation. In five out of seven of the calls he has made since August, Zimmerman identified “suspicious activity” by black males.

The state of Florida is also conducting its own investigation of the shooting.

Zimmerman’s lawyer has since confirmed that his client will turn himself into police if an arrest warrant is filed.