When "Lisa" was stalked for 16 months, several years ago in Rapid City, she felt helpless and afraid almost all the time. The situation started when Lisa, whose name has been changed here to protect her identity, ran a support group for survivors of sexual assault. She never thought one of the group members, a woman, would end up stalking her.

It started with an explicit message written in marker on the sign on Lisa's parking spot.

"I didn't even think it was really targeted at me, but as it went on, I started getting the same message left on my vehicle," she said. "It just started showing up everywhere."

During the next 16 months, Lisa received the same explicit message many more times, sometimes written by a finger in the dust on her car, sometimes in a note left under the windshield wiper.

Sometimes the messages were left on the car when Lisa was at work, other times when she was at the grocery store or coaching at a nearby school.

The stalking didn't end until after she confronted the woman stalking her and threatened to press charges. The woman stopped immediately.

She had discovered, with the help of colleagues and a law enforcement officer, that the woman was one of the members of the support group Lisa ran.

Lisa said confronting the woman was not something she, as a social worker, would recommend.

"I really could have escalated it," she said. "But I was at my wit's end."

Sharon Kallemeyn, director of Pennington County Victim Assistance, said stalking almost always escalates if there is not some type of intervention.

"Stalkers just don't fade into the sunset," Kallemeyn said. "Stalkers keep stalking until there's some sort of intervention."

That might include a protection order or jail time.

"I think the really scary thing for victims in a stalking is they don't know exactly what the person is going to do," Kallemeyn said.

She said stalking is extremely traumatic for a victim.

"When a person is stalked, they are being robbed of their sense of security and safety," Kallemeyn said. "They're constantly looking over their shoulder, and they may never feel safe in their own home."

Lisa gained weight because of the stress, and her hair began to thin.

The emotional side effects were worse.

"The feeling of helplessness was the worst part for me," she said. "I'm an independent woman, but I didn't know what to do to protect myself."

Lisa's husband was afraid, too.

"He wanted to protect me but didn't know who to protect me from," she said.