MINNEAPOLIS (AP) — A Crystal man was sentenced Wednesday to serve at least four months in jail for labor trafficking, a rare prosecution in Minnesota.

Ricardo Ernesto Batres, 47, also was sentenced Wednesday to five years probation.

Victims said in court that Batres’ threats kept them from speaking up initially.

“My family and I live in constant fear considering that Mr. Batres threatened to kill us if I reported him” to authorities, one former employee said in a victim-impact statement read aloud by a victim advocate, the Star Tribune reported.

Batres was accused of exploiting laborers at his construction company. A criminal complaint says the workers did not have authorization to be in the U.S. and when they complained about the conditions, Batres reported them to Immigration and Customs Enforcement, which deported some of them.

Batres pleaded guilty in November to labor trafficking and insurance fraud. Activists say the case is the first of its kind in Hennepin County and one of the few prosecuted in Minnesota.

He operated Crystal-based American Contractors, where as many as 12 people worked for him finishing wood framing and wallboard installation across Minnesota.