(CNN) -- The parents of Trayvon Martin, the unarmed black teen killed by a Hispanic man who claims self-defense, said Wednesday they have faith in authorities investigating the case.
"I feel confident that they're going to do a thorough investigation," said Sybrina Fulton, Martin's mother. "We're trying to be patient, even though it's been over a month. We're trying to be patient, and we're trying to press on for justice."
Fulton said she and Martin's father, Tracy, are speaking not only for their son but also for others who have died from violence.
Tracy Martin shared memories of the boy he called "my hero," who dreamed of being an aviation mechanic and wanted to make his family proud.
The 17-year-old was shot to death February 26 by George Zimmerman, a neighborhood watch volunteer, as Martin was walking back to his father's fiancee's house in Sanford, Florida. He was wearing a hoodie and carrying Skittles candy and a can of iced tea he had purchased from a nearby convenience store.
Zimmerman says he killed Martin in self-defense after the teen attacked him in the gated community.
Surveillance video taken the night of the incident at police headquarters shows Zimmerman, his hands cuffed, exiting a patrol car.
The video, first broadcast Wednesday by ABCNews.com, shows an officer looking at the back of Zimmerman's head.
Zimmerman's lawyer, Craig Sonner, previously said he believed Zimmerman's nose was broken and the back of his head suffered a cut during the incident. The video did not provide a close-up of Zimmerman's head.
The police report described Zimmerman's back as wet and covered with grass, as though he had been lying on the ground.
Zimmerman called police to report a suspicious person and said he was following Martin, despite being told by a dispatcher he didn't need to do so. Zimmerman has been questioned but not charged, police said, because they lacked evidence to contradict his account.
Martin's killing has touched a nerve across the nation, sparking calls for Zimmerman's prosecution.
ABC News reported Wednesday, citing multiple sources, that the lead investigator in the case recommended Zimmerman be charged with manslaughter after the shooting, but the state attorney's office determined there was not enough evidence to lead to a conviction.
Asked about the ABC News information Wednesday, Tracy Martin said it was "heart-wrenching."
"That just lets me know from the onset that something wasn't right about the investigation," he said.
The initial police report from the incident lists the alleged offense as "homicide/negligent" and "manslaughter/unnecessary killing to prevent unlawful act." The Seminole County state attorney's office has said evidence obtained by police was insufficient for an arrest.
In a telephone interview with ABC, a woman the network identified as Martin's girlfriend said he described Zimmerman as "crazy" shortly before his death.
The girlfriend had been talking on the phone with Martin before he was shot, the Martin family's lawyer has said. She told ABC that Martin "was walking fast when he said this man (was) behind him again."
"He come and say this look like he about to do something to him," she said. "And then Trayvon come and said the man was still behind him, then I come and say, 'Run.' "
Family attorney Benjamin Crump said last week that Martin told his girlfriend he was not going to run. According to the girlfriend's account of the call, Martin asked Zimmerman, "What are you stopping me for?" To which Zimmerman replied, "What are you doing around here?"
The girlfriend said she got the impression an altercation was taking place and that someone had pushed Martin, because the headset fell out of his ear and the phone shut off, Crump said. He said that account undercut's Zimmerman's claims of self-defense.
Tracy Martin told CNN's "AC360" on Tuesday night that he believes Zimmerman racially profiled his son.
"And then, even worse, I think the police profiled Trayvon Martin," he said.
However, there also is support for Zimmerman from an African-American friend who says he has endured his share of racial discrimination.
On Tuesday, Joe Oliver, a former CNN anchor who also worked at WESH-TV in Orlando, defended his friend, saying Zimmerman is no racist.
"I understand completely the fear and anger that's out there over this case. If I didn't know George Zimmerman, I'd be right out there, too," said Oliver.
"But I do know George, and I do know that portrayal that young black men have had. I've experienced that growing up. I get that. I understand that, but in this one spark incident, that wasn't the case. Race had nothing to do with it."
Oliver told CNN's Piers Morgan that when all the evidence comes out, "this will clearly show this was a case of life or death for either Trayvon or George."
"In my heart of hearts," he said, "I know that a good man was trying to do the right thing and something horribly wrong happened."
Tracy Martin said Wednesday that the 911 tape shows Zimmerman was profiling his son.
"Maybe (Zimmerman) wasn't a racist to (Oliver) while they sat around and talked, but clearly, on the tape, he was profiling my son, and that leads me to believe that (Zimmerman), in fact, was a racist," he said.
In a recording of Zimmerman's call to police, some people have said they hear what sounds like a possible racial slur. CNN enhanced the sound of the 911 call, and several members of CNN's editorial staff repeatedly reviewed the tape but could reach no consensus on whether Zimmerman used a slur.
Angela Corey, the special prosecutor assigned to investigate the case, said Tuesday that investigators would look into the allegations that Zimmerman used a racial slur.
Martin, who lived in Miami, was visiting Sanford after receiving a 10-day suspension from school, a family spokesman has said. An empty plastic bag found in his book bag was determined to contain marijuana residue.
Crump, Martin's parents' attorney, said information regarding the suspension was irrelevant and amounts to a smear campaign against the youth.
Florida law allows the use of deadly force anywhere a person feels a reasonable fear of death or serious injury. It has been cited in a number of justifiable homicide cases in Florida.
But as more and more information surfaces, the picture of what happened becomes more complicated.
There is Zimmerman's account as told to police. There are 911 calls with neighbors saying they heard screams, though it isn't clear whether they came from Zimmerman or Martin. There are neighbors who have gone on television, but not to the authorities, recounting what they saw.
"We believe there may have been one person who saw something," Corey said. "We believe there are a lot of what we call ear-witnesses. My lawyers are trying to track those people down."
According to the version of events police apparently gave to Martin's parents, after Zimmerman got out of his car, Martin approached him and asked "did he have a problem," Fulton said.
"Zimmerman told him 'No,' and Trayvon supposedly said, 'Well, now you do, homie,' " she said, recounting what officers told her.
Fulton said police told her Zimmerman was reaching into his pocket for a cell phone when Martin punched him and a scuffle ensued. But, she said, she does not believe that account.
"Knowing Trayvon, those are not the words of Trayvon," she said. "Trayvon is not confrontational. He would only be trying to get home."
CNN's Umaro Djau, Deirdre Walsh, Ed Payne and Tracy Sabo contributed to this report.
