Last month’s arrest of two Florida girls whose relentless cyberbullying drove twelve-year-old Rebecca Sedwick to suicide has, for many parents, refreshed anxiety.

It also points to some glaring blind spots many of us non-teens have.

Sedwick’s mother’s, Tricia Norman, thought she knew what was happening in her daughter’s online world because she checked Rebecca’s phone texts and Facebook regularly. Unbeknownst to Norman, Rebecca had signed on to a number of other apps that allowed the bullying to continue under the radar.

For parents worried about being in the dark, here are four unfamiliar places where cyberbullies might lurk. If you see these apps on your child’s phone, get familiar with them:

  • Voxer Walkie Talkie: The main feature of Walkie Talkie is its “push-to-talk” system. This free app lets you send instant texts, audio and photos, and messages can either stream live or users can listen later.
  • A social networking site with a Q&A bent. The option of anonymity is particularly worrisome.
  • Kik Messenger: A texting app that requires only user names (not phone numbers) that allows for group texting. Before jumping to her death, Rebecca Sedwick changed her name on Kik to “That Dead Girl” and sent a goodbye message to two friends.