A Casper man pleaded guilty in connection to allegations that he hit his pregnant girlfriend last month.

Sebastian Matthew Ehrler pleaded guilty to aggravated assault and battery, a felony, in Natrona County District Court Thursday afternoon. He also pleaded guilty to domestic battery, a misdemeanor.

A proposed plea agreement calls for Ehrler to serve a three-year supervised probation term. If he violates his probation conditions, he could spend three to five years behind bars. District Court Judge Catherine Wilking does not have to go along with the agreement.

According to charging documents, a Wyoming Department of Family Services agent contacted law enforcement on March 4 to report that a pregnant woman had been assaulted the previous day.

The victim, who was three-months pregnant at the time, told law enforcement she and Ehrler were traveling on CY Avenue in Ehrler's pickup truck when they got into an argument. Ehrler drove the victim to an apartment complex where he was originally to drop her off. The victim requested to be let out of the vehicle, but Ehrler refused.

Ehrler began driving faster and ran through red lights. Eventually, Ehrler and the victim began driving up Casper mountain as the argument continued.

As he continued to drive up Casper Mountain, Ehrler punched the victim in her face. As she cried and held her hand over her eye, Ehrler told her to "grow up" and struck her arm.

When the victim told Ehrler she was going to call the police, he threatened to either wreck the truck by driving off a cliff or get into a high-speed chase with police.

Ehrler said he and the victim would, "go out with a bang" if she called law enforcement.

Speaking with law enforcement, the victim recalled a separate incident in which she and Ehrler had an argument. Ehrler punched the victim in her arm, who then threw a drink at him and ran away.

During the investigation, authorities noted injuries to the victim consistent with her account of events.

Speaking in court Thursday, Ehrler said he hit the victim because she disrespected him.

A sentencing date has not yet been set.