A longtime employee of a Florida trucking company drove around Saturday shooting former co-workers and his onetime boss, killing two and wounding two, authorities said. The gunman then killed himself.

Hubert Allen Jr., 72, shot the men at several locations in and near the North Florida community of Lake Butler, according to a Union County Sheriff’s Office news release.

Authorities said Allen shot and killed former co-worker Rolando Gonzalez-Delgado, 28, around 9 a.m. then went a short distance and shot his former employer, 80-year-old Marvin Pritchett.

A few minutes later, he pulled over where another former co-worker was driving a farm tractor, exchanged words with him and then fired one shot from a shotgun, authorities said.

That victim, 66-year-old Lewis Mabrey Jr., was in good condition and receiving surgery for a broken arm and other injuries.

Not long after that, Allen went to the company’s headquarters and shot 44-year-old David Griffis in the stomach, the release said. Griffis was in critical condition.

Authorities said Allen then returned to his Lake Butler home and killed himself. He was described as a longtime employee of the trucking company.

Investigators were working at the five shooting scenes late Saturday and interviewing witnesses and company employees. The news release said they were working to determine a motive.

Messages seeking further comment from the sheriff’s office weren’t immediately returned.

The trucking company’s website says it employs 400 people and owns hundreds of vehicles.

It said Pritchett started the company in 1980, ten years after purchasing a Florida timber business. The company’s main number rang unanswered.