As the prosecutor in Florida sought to sort out the facts in the killing of Trayvon Martin, attention shifted Tuesday to Washington, where Martin's parents and family attorney attended a forum on racial profiling, hate crimes and "stand your ground" deadly force laws.

"My heart is broke," his mother, Sybrina Fulton, told reporters after the meeting, which was sponsored by Democratic members of the House Judiciary Committee. "But it breaks even more to know that we have not gotten justice yet."

"He's sadly missed," his father, Tracy Martin, told the forum, which was packed to capacity. "And I'll continue to fight for justice for him."

Martin, who was African-American, died February 26 when neighborhood watch volunteer George Zimmerman, who is Hispanic, shot him after calling police to report him as a suspicious person. Zimmerman has not been arrested.

"We honestly believe that Trayvon Martin is dead today because he was racially profiled, and because of that, it escalated, and it led to the fatal altercation with George Zimmerman," said Benjamin Crump, a lawyer for the family.

Zimmerman's family has said he has been wrongly portrayed as a racist.

Rep. Frederica Wilson, D-Florida, called Trayvon Martin a "victim of a botched police investigation full of incompetence or intelligent mismanagement." She added, "Trayvon was hunted, chased, tackled and shot. Ill-conceived laws and lax gun laws all contribute to this tragedy. Mr. Zimmerman should be arrested immediately for his own safety."

The shooting and the lack of an arrest have generated outrage. On Tuesday, some members of Congress took to the House floor to speak about the case ahead of the afternoon forum.

"Trayvon Martin is one of the two people who at least deserve a fair trial," said Rep. Al Green, D-Texas. "He deserves a fair hearing on what happened that day. He cannot speak for himself, but there is evidence that speaks volumes about what happened on this occasion."

House Speaker John Boehner, R-Ohio, called the case tragic but declined to elaborate. "It's being investigated by state and federal officials, which I think is appropriate, and I think I'll leave it at that," he said.

Meanwhile, the special prosecutor in the case continued to try to determine what happened.

"We believe there may have been one person who saw something," Angela Corey said. "We believe there are a lot of what we call ear-witnesses. My lawyers are trying to track those people down."

She said the "political outcry" about the case makes her job harder. "Any time there is a misunderstanding of the process, based on what we are required to do under Florida law, it does make our job more difficult," she said.

Zimmerman has said he killed Martin in self-defense after the unarmed teen attacked him in the gated community. Martin was returning to his father's fiancee's house after buying Skittles candy and a can of iced tea from a nearby convenience store. Zimmerman was questioned in the shooting but has not been charged because, police said, they did not have evidence to contradict his account.

Corey said investigators would look into the allegations that Zimmerman uttered a racial slur on the phone with police just before the shooting. CNN enhanced the sound of the 911 call, and several members of CNN's editorial staff reviewed the tape but could reach no consensus on whether Zimmerman used a slur.

On Monday, Sanford police confirmed an Orlando Sentinel report that cited unidentified authorities saying Zimmerman told them Martin punched him in the nose after the two exchanged words.

Police said Monday that the Sentinel account is "consistent with the information provided to the State Attorney's office by the police department." The newspaper reported that Zimmerman said Martin then repeatedly punched him and slammed his head onto the sidewalk.

Tapes of 911 calls include neighbors saying they heard screams, though it wasn't clear whether they came from Zimmerman or Martin.

Two women who live nearby have said they heard someone in distress, and then a gunshot. Mary Cutcher and her roommate, Selma Mora Lamilla, said Monday they ran to about 10 feet from where Martin's body lay.

"(Zimmerman) was standing over the body, basically straddling the body with his hand on Trayvon's back," Cutcher said, adding that they called three times to him before he finally asked them to call police. "It didn't seem to me that he was trying to help him in any way."