(CBS) -- The significance of George Zimmerman's February 26, 2012 call to non-emergency dispatchers, placed in the minutes before he shot and killed unarmed Florida teen Trayvon Martin, is likely to be a key issue at the former neighborhood watch captain's upcoming trial. But whether the call will be a boon for prosecutors continues to be a subject of debate.
Some experts say the call, in which Zimmerman says he is following Martin in a Sanford, Fla. gated townhome community, could be crucial to prosecutors who are attempting to refute his claim that he killed the teen in self- defense. But an attorney for the 29-year-old former neighborhood watch captain said in a recent television interview that there's "no evidence" that Zimmerman continued to pursue the teen after a dispatcher told him to stop.
"This guy looks like he's up to no good or he's on drugs or something," Zimmerman says in the recording, after calling to report a suspicious person. "It's raining and he's just walking around looking about."
When the dispatcher asks if Zimmerman is following the teen, he replies, "Yeah."
"We don't need you to do that," the dispatcher says. Zimmerman replies, "OK."
At trial, the recording may prove more beneficial for prosecutors because Zimmerman identifies Martin as an intruder, said David LaBahn, president and CEO of the Association of Prosecuting Attorneys.
"He's a quote, 'neighborhood watch guy,' he sees a black male wearing a hoodie coming through the complex, the implication is there's some assumption this guy doesn't belong," LaBahn said. "...A more traditional call in a self-defense situation is, 'Someone's trying to kill me.'"
Who started the confrontation in the minutes before Martin's death is likely to be another central issue at trial.
"Basically, Martin would be alive but for the fact that Zimmerman chose to one, arm himself, two, follow him, three, go out to confront him, and four, shoot him to death," LaBahn said.
Zimmerman's defense attorney Mark O'Mara, however, offered a different perspective on the call during an interview on MSNBC's "Politics Nation with Al Sharpton." When asked how his client could claim self defense when he was following Martin with a gun, O'Mara said there was no evidence to suggest Zimmerman continued following Martin "after the dispatcher said, "You don't have to do that." Mr. Zimmerman's answer was, "OK."
"The question is when he was pursuing him and if he continued to pursue him," O'Mara said. "That's what the jury has to determine. If you suggest Zimmerman was at least at one point pursuing, following Trayvon then he can't argue any type of self-defense, that's just not the law. Really, it comes down to what happened when the two people, two individuals got together - what happened at that point that would justify either one of them doing something to the other."
Jose Baez, lead defense attorney for the Casey Anthony case, told Crimesider the fact that Zimmerman himself made the call may lend weight to his self-defense claim.
"You don't call the police if you're trying to murder someone," Baez said.
A judge is set to rule on the admissibility of another key recording this week, in which a state audio expert claims Martin is heard in the background of a neighbor's 911 call saying, "I'm begging you." Other experts have said the shouts were a mix of Martin and Zimmerman.
The judge is scheduled to rule whether the state expert used scientifically acceptable techniques, the Orlando Sentinel reports.
The trial is set to launch with jury selection June 10.