Sanford, Fla. ? George Zimmerman once took criminal justice classes at the community college and was practically a one-man neighborhood watch in his gated part of town, calling police close to 50 times over the past eight years to report such things as slow-driving vehicles, strangers loitering in the neighborhood and open garages.

Now, suddenly, people are wondering if the 28-year-old Zimmerman is an earnest if somewhat zealous young man who was just looking out for his neighborhood, or a wannabe cop who tried to take justice into his own hands.

He has been at the center of a growing furor over vigilantism, self-defense and racial profiling since he shot and killed an unarmed black teenager who was walking through his neighborhood Feb. 26 carrying only a bag of Skittles and an iced tea.

Zimmerman, a light-skinned Hispanic, has claimed self-defense in the slaying of 17-year-old Trayvon Martin and has not been charged, but many black leaders are demanding his arrest, and state and federal authorities are investigating. Florida’s Stand Your Ground law on self-defense gives people wide latitude to use deadly force.

Attorneys for Martin’s parents say Zimmerman is a “loose cannon.”

“He’s a wannabe police officer,” lawyer Benjamin Crump said. “Why did he have a gun?”

But some neighbors welcomed his vigilance, at least before the shooting.

Samantha Leigh Hamilton, an auto-dealership employee who has lived on Zimmerman’s street for about a year, said that she once left her garage door up and Zimmerman noticed it while out walking his dog. He notified another neighbor, who let Hamilton know.

“The only impression I have of George Zimmerman is a good one,” Hamilton said Wednesday.

Hamilton said another neighbor, a black woman, would regularly inform Zimmerman when she was out of town so that he could keep an eye on her place. Hamilton said that when she moved into the middle-class, racially mixed community of about 250 identical townhouses, the black neighbor told her, “Hey, if you need anything, you picked a really good area, since George is part of our neighborhood watch.”

Zimmerman, who was captain of the neighborhood watch and licensed to carry a gun, made 46 calls to police since 2004, according to department records.

In one police call report, the dispatcher noted that Zimmerman was calling about a vehicle “driving real slow, looking at all the other vehicles in the complex and blasting music.” In another call from last August, Zimmerman reported on two black male teens in the neighborhood. He considered them suspicious.

A police spokesman in Sanford, a city of 53,000 people outside Orlando that is 57 percent white and 30 percent black, did not return calls for comment about Zimmerman’s repeated reports.