REMEMBER WHEN you were a kid, you'd fall and skin your knee and a scab would form?

Mom would tell you not to touch the scab, picking at it would be bad for you, but sometimes it would itch so much you just couldn't help yourself. You'd scratch the scab, getting a moment of relief, then it might tear open, bleed and expose you to infection.

Tuesday afternoon, the angry neighbors of Kensington scratched at a scab named

Jose Carrasquillo, a suspected child rapist, and put him in the hospital in critical condition.

I can understand how good that must have felt. I'd want to take a softball bat to a child rapist. It would be a good thing to do, but not the right thing to do.

Carrasquillo was just a suspect. He was not even charged, let alone convicted.

Picking at this scab - kicking the bejabbers out of a suspect - feels good, but exposes us to an infection, vigilantism.

Despite the momentary pleasure it gave the participants - and their action was basically brushed off by police - it went too far. They enjoyed it too much.

It seemed to be an example of what's called "social facilitation, where somebody starts something and everyone piles on," says Temple University psychologist Frank Farley, a former president of the American Psychological Association.

This wasn't a case in which people had to take the law into their own hands because the law had turned a blind eye. Our cops wanted this guy and were going to get him. All the neighbors had to do was grab him and sit on him until cops arrived.

One surprising thing was the casual way the 26-year-old Carrasquillo, who was on probation, strolled through his neighborhood. With a police sketch, a damn good likeness of him, in the papers and on TV, you would think he would have gone underground.

See the consequences of not reading papers or watching TV news?

The crime itself - a brutal attack on an 11-year-year girl as she walked to school - was evil enough to infuriate the community. Its desire for justice might have been further fueled by a $10,000 reward offered by the Fraternal Order of Police. I don't criticize the FOP for putting up the reward money.

The community action, excessive in the form it took, was at least a welcome change from the norm in one respect. In a city where too many people share a simple-minded "don't snitch" mentality, this was the flip side of the coin. But all the cops wanted and needed was information. What they got was a bloody suspect, for whom few have sympathy.

Police Commissioner Charles H. Ramsey said the community took the crime "to heart," but he stopped short of either approving or condemning their actions.

"Justice, community-style," said a happy resident who declined to be identified. "It's a beautiful thing."

No, sorry, it's an ugly thing, when done like this. You can't allow the law to be subject to situational or optional ethics.

It is no more acceptable for neighbors to bash a suspect when they "feel" he's guilty than it is for a judge to ignore the law to find some way to impose a light sentence. It is no more acceptable when frustrated cops, unable to rightfully collar someone they "know" to be a drug dealer, plant evidence on him. Once you start doing wrong in the name of doing right, it's hard to know where to stop.

When you take the law into your own hands, that is the end of law. You become a vigilante.

No matter how good it feels to scratch the scab, don't do it. *

E-mail stubyko@phillynews.com or call 215-854-5977. For recent columns:http://go.philly.com/byko.