(Reuters) - George Zimmerman, the man whose fatal shooting of unarmed Florida teenager Trayvon Martin a year ago captured the nation's attention, wears a disguise or body armor in public as he feels threatened, his lawyer said on Wednesday.

Zimmerman remains in hiding and "can't go out in public without wearing a disguise or body armor," defense attorney Mark O'Mara told CNN.

Zimmerman claims to have mistaken Martin, who was 17, for a burglar and to have shot him in self defense after a confrontation on February 26, 2012.

After police initially questioned and released Zimmerman, citing Florida's so-called Stand Your Ground gun law, celebrity protests and nationwide public demonstrations prompted a re-investigation that led to his arrest for murder.

Martin's parents attended a one-year anniversary vigil in New York City late Tuesday, and continued their call for stricter gun laws nationwide.

Passed in 2005, Florida's Stand Your Ground law allows people to use lethal force in self-defense. Numerous states have since passed similar laws.

Critics of the law say it encourages vigilantes and fosters gun violence.

The uproar after Martin's killing led the local police chief to step aside and the governor to appoint a special prosecutor, who charged Zimmerman with second-degree murder.

The trial is scheduled for June.

O'Mara will ask a judge to dismiss the charges on the grounds of self-defense, at a much-anticipated pre-trial hearing on April 29.

O'Mara said Martin badly beat Zimmerman after a confrontation inside a gated community in Sanford, Florida.

"George didn't have an opportunity to retreat, so calling this a 'Stand Your Ground' hearing in not accurate," O'Mara told CNN Wednesday.

O'Mara said Zimmerman was "very stressed (and) very worried" about the trial and has remained in hiding for the past year.

(Reporting by Chris Francescani; Editing by Daniel Trotta and Bernadette Baum)