NEW YORK -- Tough-talking former prosecutor Nancy Grace is leaving her prime-time show on the HLN network in October.

The CNN sister station said Grace told her staff Thursday that her show would be ending after 12 years. Grace, 56, said in a statement that she'll be leaving "with a full heart and endless gratitude."

She hasn't announced any specific new plans, and HLN wasn't saying Thursday what type of show would replace her.

Get Breaking News Delivered to Your Inbox

Grace, who turned to law after her fiancee was murdered in college, worked in an Atlanta-area district attorney's office and became a go-to television personality commenting on trials in the post-O.J. Simpson era. Her HLN show focused on missing children and crime victims. When Grace formed an opinion on a case, she pursued it with a barracuda-like intensity.

Her popularity boomed when missing children cases like Caylee Anthony, Natalee Holloway and Elizabeth Smart dominated mainstream news. But fewer of those cases have broken through to wide attention in recent years. In the age demographic that television executives seek, her audience dropped to a third or quarter what it was in its peak years.

"She gave a voice to the voiceless and we are extremely grateful for her contributions to the network," said Ken Jautz, HLN's chief executive.

Grace said the show "created an unparalleled platform that gave crime victims a voice and succeeded in helping to find missing people and solve unsolved homicides."

"I will continue my fight for justice across a variety of traditional and new media, where victims' voices can reach an entirely engaged audience," she said.