HOULTON, Maine — When Charles “Frank” Dorr was hit with drug charges on Wednesday evening, he already was sitting in Aroostook County Jail on unrelated charges.

While information about those charges could not be obtained Wednesday evening, police said Thursday the charges were lodged against Dorr after he had a violent argument with a female companion in the downtown area, during which he reportedly twice struck the 31-year-old woman with a car he was driving.

Dorr, also 31, was charged Wednesday evening with trafficking in marijuana and prescription narcotics.

The Maine Drug Enforcement Agency and the Houlton Police Department had been investigating Dorr’s activities for several weeks, and the MDEA executed a search warrant Wednesday at Dorr’s home while he was jailed on the unrelated charges.

Police Chief Butch Asselin said Thursday the charges of domestic violence reckless conduct, domestic violence assault, and driving to endanger came about on Monday evening after Dorr was arrested on Mechanic Street.

According to the chief, police officers were called to Mechanic Street just before 9 p.m. after receiving a report of a couple arguing on the street. Officers Randall Wilson, Jared Sylvia and Sgt. Eric Crouse investigated the incident.

Asselin said a woman who had a relationship with Dorr told the officers that during an argument with Dorr he got into a car and backed over her, knocking her to the ground.

“The victim said that she remembered looking up and seeing the car coming over her,” Asselin said Thursday.

After the woman got to her feet, Dorr allegedly turned the car around, accelerated and came back toward her. She was able to jump onto the hood of the car but was thrown to the ground.

Dorr was arrested on the felony and misdemeanor charges and then taken to jail. The woman, who is not being identified because she is a victim, was taken by the Houlton Ambulance Department to Houlton Regional Hospital for treatment and later was released.

Asselin said that Dorr’s incarceration on the domestic violence charges “accelerated the drug investigation.”

The search warrant on Wednesday was obtained “primarily to search for records of previous drug trafficking by Dorr,” said Asselin. A number of items, including a personal computer, were taken as evidence and will be analyzed over the coming days.

Dorr has a prior criminal history and became a registered sex offender after he was convicted in 2005 in Aroostook County Superior Court of unlawful sexual contact. Other convictions include operating a motor vehicle while license suspended or revoked and violating condition of release.

Dorr remained at the Houlton jail Thursday.