CRANDON, Wis. -- Police say a law enforcement officer opened fire at a house party in Crandon, Wis., killing six people before he was taken down by a sniper, reported Milwaukee-area television station WISN-TV.

Video: Off-Duty Officer Shoots, Kills 6

Crandon Mayor Gary Bradley said late Sunday afternoon it was his understanding that the suspect, 20-year-old Tyler Peterson, was killed by police in the melee.

"He was brought down by a sniper," Bradley said.

A press conference Sunday confirmed that seven people, including the alleged gunman, were dead in the shooting.

A state patrol officer said the shooter was an employee of the Forest County Sheriff's Department and a part-time officer for the Crandon Police Department.

Others were injured in the gunfire. One young man was treated and released from St. Mary's Hospital in nearby Rhinelander, a hospital representative said. A second young man is being treated at St. Joseph's Hospital in Marshfield. His condition is currently unknown.

The victims are young adults, and Bradley said that several parents still have not been notified. Crandon High School celebrated Homecoming last Friday.

"It's a pretty tragic situation here," said Forest County Supervisor Tom Vollmar. The families of victims are congregating at Praise Chapel, at 200 E. 6th St. in Crandon, seeking comfort.

A woman who lives near the duplex where the shooting occurred said she heard a number of shots and tires squealing. Her husband said it's hard to accept that someone in law enforcement was behind the killing.

It's not yet clear what the alleged gunman's motive was. But the mother of a 14-year-old victim said the suspect may have been a jealous boyfriend.

One teenager said the victims included Crandon High School students, recent graduates and the ex-girlfriend of the suspect.

Another teenager said she was told about 10 people were at a party at the ex-girlfriend's apartment at the time of the shooting.

The Crandon School District has called off Monday classes.

Crandon is a very small town of about 2,000 people about two hours north of Green Bay. It's in an area known for logging, and fishing, hunting and snowmobiling. It's also home to the World Championship Off-Road Races.

Bradley said Crandon is a strong community and will prevail.