UPDATED 06/21/12 11:45 a.m.

CHICAGO (CBS) — It was an attack so vicious that the victim was left with a massive gash across his throat and it happened just blocks from Wrigley Field.

CBS 2’s Mike Puccinelli has the story of an unprovoked attack that has left its victim scarred physically and emotionally.

Michael Schmidt was walking his dog west on Byron Street near Wayne Avenue late Sunday night, when he says he encountered a person he described as a sociopath.

“An individual came up from behind, grabbed my chest with his left hand, took a 10-inch blade, slashed my throat from left to right,” Schmidt said. “He then took about ten steps back and just stood and watched me bleed.”

The Wrigleyville resident said he lost a massive amount of blood, and now has more than 40 stitches in his throat. He said, as bad as it is, emergency room doctors told him it could have been worse.

“When he made the cut, I just jerked back instinctively, and they said had I not, he would have severed an artery,” said Schmidt.

Police released this sketch of a man suspected of a knife attack a few blocks from Wrigley Field. He is described at 6 feet 1 inches tall, about 30 years old and wearing a white T shirt.

Because the attacker didn’t flee right away, Schmidt said he got a real good look at his face as he stood under a street light. He filed a police report and had police send over a sketch artist, so wanted posters can be created and distributed in the neighborhood and in the media.

A police community alert about the attack was released on Thursday morning. The alert included a sketch, and described the assailant as an African-American male around 30 years old, standing about 6 feet 1 inch tall with a dark complexion and an afro hairstyle.

He was last seen wearing a white T-shirt with black stripes and black shorts.

After the stranger attacked him, Schmidt said he asked the man why he did it.

“He never said one word. He stood there for about ten seconds, turned around, walked away,” said Schmidt.

Schmidt said he believes his dog might have saved his life, by stepping in front of the attacker after the initial cut.

Had his dog not been there, Schmidt believes the attacker might have killed him.

“The look in his eyes, it was just … I will never forget it,” said Schmidt.

After his throat was slashed, Schmidt stumbled down the street to the intersection of Clark and Byron streets. That’s where a passerby called an ambulance and rushed him to Advocate Illinois Masonic Medical Center.

He said he’s going public about the attack, so what happened to him doesn’t happen to anyone else.

“He had a very crazed look on his face. No look of remorse whatsoever,” Schmidt said.

He called his attacker a sociopath, and said he fears the man is still out there roaming free.

“I know he is,” said Schmidt.

Editor’s note: This story has been updated to remove reference to blood loss and to clarify that the victim did file a police report.

Mike Puccinelli