Trayvon Martin’s mother testified before a Senate panel Tuesday, urging states to amend their “stand-your-ground” laws.

Sybrina Fulton described how her son, 17, was walking home unarmed in Sanford, Fla., when he was shot and killed by neighborhood watch volunteer George Zimmerman.

Zimmerman’s July trial captured the nation’s attention and sparked heated debate over stand-your-ground laws after a jury found him not guilty of second-degree murder and manslaughter.

A stand-your-ground law allows a potential crime victim in fear of grave harm to use deadly force in public places; it also eliminates the duty to retreat. Between 2000 and 2010, 22 states enacted some form of a stand-your-ground law.

Although the Zimmerman defense did not mention such laws at his trial, one of the six jurors in the case said Florida’s stand-your-ground law was key in the jury’s verdict.

Fulton said she attended the hearing of the Senate Judiciary Committee “to let you know how important it is that we amend this stand-your-ground because it did not work in my case. The person that shot and killed my son is walking the streets today, and this law does not work.”

Sen. Dick Durbin, D-Ill., who presided over the hearing, cited Texas A&M University research suggesting about 600 homicides a year could be linked to stand-your-ground laws and found no indication that the laws deter crime.

Durbin said the laws encourage a “shoot first” mentality.

Sen. Ted Cruz, R-Texas, however, questioned the purpose of the hearing, saying the federal government has no authority over state self-defense laws – and that states should make their own judgments. Cruz also said self-defense is a bedrock liberty and the stand-your-ground laws apply only to cases in which there is an imminent attack that could cause death or serious injury, not to violent aggressors.

John R. Lott Jr., president of the Crime Prevention Research Center, urged the senators to consider that the vast majority of cases in which the defendant invokes stand-your-ground protection involve crimes between people of the same race.

He cited a Tampa Bay Tribune study of 112 Florida cases that found 90 percent of African-American victims were killed by another African-American.

“The people who are most likely to be victims of crimes are poor blacks who benefit from the option of being able to protect themselves,” Lott said.