Teen upset over Snapchat message to girlfriend fatally stabbed fellow student, police say

Police say a 16-year-old fatally stabbed a fellow student because he was upset about a Snapchat message sent to his girlfriend.

Police say Matthew Joseph Fischer of Mount Pleasant was visiting his girlfriend's home in the bedroom community just outside Charleston on Sunday when he saw the message from 17-year-old Lucas Cavanaugh on her iPod. The message was sent through Snapchat, a photo-and-text app on which messages are visible for only a brief time.

An arrest affidavit says the message angered Fischer, and he messaged Cavanaugh, saying "Come over" and "I'll kill you man." Police haven't released details of the content of the original message.

Authorities say Cavanaugh, of nearby Sullivans Island, came to the house and the two fought.

Fischer is charged as an adult with murder and possession of a knife during a violent crime.