Miami-Dade Circuit Judge Beth Bloom based the decision on Florida's controversial "stand-your-ground" law, which provides considerable leeway for use of deadly force without retreating when someone is threatened in a confrontation, The Miami Herald reported.
The self-defense law has come under scrutiny after the fatal shooting of Trayvon Martin by a self-appointed neighborhood watch volunteer.
Bloom said Greyston Garcia was immune from prosecution in the Jan. 25 killing of Pedro Roteto, who swung the 4- to 6-pound bag of radios at Garcia just before the stabbing.
The Herald said police had portrayed Garcia as a vigilante and said he had chased Roteta more than a block before the stabbing.
In her order, Bloom wrote Garcia "was well within his rights to pursue the victim and demand the return of his property. ... The defendant had no duty to retreat and could lawfully pursue a fleeing felon who has stolen his property."
Garcia didn't call police or 911 but went home and fell asleep, Bloom said in the ruling.
Miami-Dade Chief Assistant State Attorney Kathleen Hoague said her office would appeal the decision because "we feel the judge abused her discretion."
"The law does not allow for you to use deadly force to retrieve your property. She, in effect, is saying that it's appropriate to chase someone down with a knife to get property back," Hoague said.