Glass and a door lie on the ground at the scene of an explosion at an Air Force recruiting office in Bixby, Okla., Tuesday, July 11, 2017, after an explosion Monday night outside an Air Force recruitment office. The center was closed at the time and no one was injured. The explosion is being investigated as a possible act of domestic terrorism, but the late-night blast could also have been a horrible prank, a federal agent said Tuesday. (Mike Simons//Tulsa World via AP) (Associated Press)

BIXBY, Okla. — Federal authorities said Tuesday that they are no longer investigating a pipe bomb explosion that damaged a northeast Oklahoma Air Force recruiting station as a possible act of domestic terrorism, adding that the blast could be the work of a disgruntled employee or a prank.

FBI Special Agent Jessi Rice said the explosion in the Tulsa suburb of Bixby is not being called domestic terrorism because investigators have not determined a motive and have not identified a suspect. Rice said the blast currently is a criminal investigation into the use of an explosive device.

“We don’t know if it was a disgruntled employee, an act of terrorism or someone playing games,” Rice said at a news conference.