He apparently told an adult who advised him to surrender, which he did at the 122 precinct this morning.
The teen is about 14 and gave no specific reason for committing the vandalism, officials said.
The boy was expected to be charged as a juvenile with criminal mischief, according to the NYPD.
Police say they are still investigating Grimm's computer server, but indications are a Grimm campaign staff member may have mistakenly deleted the hard drive by using a Linux rescue disk in the Windows machine.
Nobody realized the staffer had used the disk until the data was discovered missing. The deleted information was successfully backed up.
Grimm's campaign issued this statement: "It is possible that a campaign volunteer could have inadvertently compromised the computer and failed to report it. We are still letting the police finish their investigation. They are reviewing our hard drives."
Get Eyewitness News Delivered