This is all I know at the moment from an LRPD release:
On Oct. 5 at approximately 1549 hours, Officers received a call to UAMS Emergency Room in reference to a subject being treated for injuries caused by an explosion. When Officers arrived they made contact with Ms. Melinda Lamb (W/F 09-20-60) who advised that she transported her boyfriend, Mr. Aaron Lewis (W/M 03-26-74) to the emergency room because he was at his residence (#4 Ohio Cove) packing a bomb between his legs when it exploded. The detectives, the ATF, and Rock Fire Department Bomb Squad were notified and responded. Mr. Lewis was being treated for serious injuries to his legs and feet. The case was turned over to the ATF, because of other ongoing investigations involving Mr. Lewis. A suspected Meth Lab was located in the residence and LRPD Narcotics Officers and LRFD Haz Mat helped clean up the lab.
I asked Lt. Terry Hastings for any theories about the bomb. He said that was ATF work, but added: "I think this was a guy just playing around. The meth Lab says a lot."