If you have not heard the name Trayvon Martin by now, you should have.

What we know about the 17-year-old is that he was shot to death in Sanford, Fla., last month by George Zimmerman, a self-appointed neighborhood crime-watch captain.

Martin, who was walking home from a local convenience store after buying a bag of Skittles and an iced tea, was wearing a hoodie and talking on the cellphone with his girlfriend.

Apparently that was enough for Zimmerman to consider him suspicious.

Zimmerman called 911, telling a police dispatcher: “This guy looks like he is up to no good. He is on drugs or something.”

When asked, Zimmerman acknowledged he was following Martin. Police dispatchers told him to stop.

The National Crime Prevention Council stresses that “watch groups are not vigilantes and should not assume the role of the police. Their duty is to ask neighbors to be alert, observant, and caring — and to report suspicious activity or crimes immediately to the police.”

It would appear in this case that Zimmerman overstepped these bounds, and the result is that a young man’s life came to an end.

The neighborhood crime-watch program is not intended to replace police. Limits are there to protect innocent victims as well as neighborhoods.