MILWAUKEE, Wisconsin - A sheriff’s deputy went on a shooting rampage Sunday, killing his ex-girlfriend and five other youths at a house party in a small town in Wisconsin, authorities said.

The 20-year-old deputy and all those shot were all part of a close-knit group of friends, sources said.

Two of those killed were seniors at Crandon High School, which had just celebrated a homecoming victory Friday night. Another girl was just 14 years old, sources said.

Police have confirmed that a 19-year-old was also shot and in critical condition.

Sources identified the gunman as Forest County Sheriff’s Department Deputy Tyler Peterson.

The shooting began just before three o’clock in the morning and within hours the deputy was also dead after an intensive manhunt.

“He was brought down by a sniper,” said Crandon Mayor Gary Bradley.

The 2,000 or so people who live in the town near the Canadian border spent much of Sunday in “lockdown,” with residents forbidden from venturing out on the streets.

The shootings in Wisconsin may have people wondering how local law enforcement officers are chosen and what kind of screening process do we have in our community.

At the Ironton Police Department, Police Chief Jim Carey said that applicants must pass several screenings.

“A lot of ours is dictated by civil service tests,” Carey said. “Whenever we have an opening, Civil Service does an advertisement.”

After a written test and a physical fitness test, Civil Service gives the list of qualified candidates to the police department.

“Once that process is done, we look at the candidate’s background check,” Carey said. “We check former schools, employers, and we check with neighbors.”

Before hiring, candidates must have a complete physical and they have to pass a drug test.

Each candidate must become certified by the state of Ohio. In order to do that, there are 80 sites throughout Ohio that provide training in certain categories, including private security, local corrections, jail personnel, bailiffs and public defender investigators.

The Ohio Peace Officer Training Commission approves and monitors each school that offers the training.

Some of the topics covered in depth are administration, legal, human relations, firearms, driving, patrol, civil disorders, traffic, investigation and physical conditions.

In the peace officer category, a person can attend on their own time at their own expense or who have been appointed to a peace officer position. The student must attend a minimum of 550 hours and possible additional hours required by the school.

After the basic training, students must pass a state certification examination.

The Ohio Peace Officer Training Academy in London trains approximately 10,000 officers each year. The academy was accredited by the Commission on Accreditation for Law Enforcement Agencies on July 31, 2004. OPOTA was one of the first four agencies in the world to earn the CALEA Public Safety Training Academy Accreditation Award.

“A lot of vocational schools offer the training,” Carey said. “They are still supervised and accredited through the Ohio Peace Officers Academy. In order to be a police officer in the state of Ohio, they have to have the certification.”