WILLISTON, N.D.-A former landscaper pleaded guilty Monday to killing a co-worker over a dispute and will likely spend about 16 years in prison for that and other charges.

Tovias Carrillo entered guilty pleas to murder, two counts of terrorizing, aggravated assault and tampering with physical evidence.

Authorities say Carrillo shot Juan Palacios, 51, in the head in January 2014 after a heated disagreement began between the two men at the Williston landscaping business where they worked. Carrillo disposed of the body in a field east of Williston, leading investigators to the site after confessing to the shooting about a week later, records say.

He also threatened to kill two other men around the same time, according to police.

Another violent encounter took place in December 2014 at the Williams County Correctional Center, where Carrillo attacked another inmate with a broken coffee cup and tried to hide his

bloody clothes afterward.

He is also facing charges for an attack on an inmate late last year at the Bismarck state prison.

Williams County prosecutor Nathan Madden recommended a sentence of 30 years with 19 to serve for the murder of Palacios, and concurrent terms of four years each for the remaining sets of allegations. As part of a plea agreement, Carrillo will receive credit for the two years and seven months he's spent behind bars since his January 2014 arrest, bringing the total sentence to about 16 years.

Following his release, Carrillo, 51, will probably be deported back to Mexico.

"I am under the understanding that immigration will put a hold on him," defense attorney Steven Mottinger said. "These are automatically deportable offenses."

Carrillo asked a number of questions of District Judge David Nelson during the hearing, and claimed that the reported circumstances behind the terrorizing charges did not happen.

"That's not true. That took me by surprise," he said. "I need to get this off my chest and tell you what is true and what is not true."

Nelson sentenced him to four years for tampering with evidence, and ordered a presentence

investigation prior to handing down the remaining prison time. A date has not yet been set for

sentencing on the other charges.

As part of the plea agreement, a charge of possession of a weapon in a correctional facility was