Each year, for the past three years, LGBT advocacy groups have tallied the killings of more than 20 transgender people in the U.S. Yet state or federal hate crime laws are rarely used to prosecute the slayings.

Now many LGBT-rights groups are questioning the effectiveness of the laws, saying they sometimes focus too tightly on individual acts without addressing underlying bias or wider violence. The volatile issue was back in the spotlight this week as Missouri authorities investigated the killing of a transgender teen who was stabbed in the genitals and had her eyes gouged out.

Investigators insist — without specifying a motive — that Ally Lee Steinfeld’s death was not the result of anti-transgender hate.

“You don’t kill someone if you don’t have hate in your heart,” said James Sigman, the sheriff in Missouri’s Texas County. “But no, it’s not a hate crime.”

Even if the case were deemed to fall under Missouri’s hate crime law, it probably would not result in a heavier penalty, since first-degree murder is already punishable by execution or life imprisonment.

Missouri is one of 17 states with hate crime laws that cover offenses targeting people on the basis of their gender identity. But those provisions have led to few prosecutions.