Police are searching for man who they say killed one man and injured five others, one critically on Sunday.

The suspect is 5-feet 8-inches tall, between 20- to 25-years-old, and was wearing a dark hooded sweatshirt and dark pants, according to investigators.

Nineteen-year-old Dane Freeman of Cambria Heights was shot in the head and pronounced dead on the scene, according to cops, and they say Freeman was one of the six victims of the shooting spree.

Detectives say Freeman gathered Sunday morning around 2:30 a.m. to be with friends and have fun at a party that was supposed to be an informal reunion of former students of Tri-Community School 231.

The junior high school is just five blocks away from 182nd Street, near the intersection of 145th Drive in Springfield Gardens, where the shooting occurred.

The organizers of the reunion posted the invitation on Facebook and Twitter, and witnesses said hundreds of people -- many of whom never even went to the school -- showed up.

"Once you put something on Facebook, it's out in the universe," said James Sanders, Jr., the local city councilmember, "People in other countries know about it. There's no way you can control it."

Witnesses also said the number of people and their actions got out of hand, and gunshots rang out.

"People scrambling all over the place. Lights went on all over in the yards from kids scrambling and everything," is how one eyewitness described the scene.

He added that a group of young men on motorcycles pulled up to the outdoor party. A fight may have broken out and then there was gunfire.

When it was over, five people were injured, including one unidentified 23-year old man, who is in critical condition at Jamaica Hospital with a gunshot wound in his back.

Two other young women -- a 21-year-old who was shot in both hands and a 22-year-old shot in her left shoulder -- were also transported to Jamaica Hospital, and listed in stable condition.

Another victim, a 21-year-old man, was taken to the same hospital in stable condition for a gunshot wound to his leg. The other man, 25, was shot in his left leg and transported to North Shore University Hospital in Manhasset, Long Island in stable condition.

Police urge anyone with any information about the shooting to contact NYPD Crimestoppers or call its confidential tip line 1-800-577-TIPS.