A Dorchester state representative was arrested Sunday morning after he allegedly punched a woman inside a car as they were driving near a Northeastern University dormitory, authorities said.

Representative Carlos Henriquez was arrested at about 4:30 a.m. on charges of domestic assault and battery and domestic kidnapping, said Boston police Officer James Kenneally, a department spokesman.

Police said that Henriquez and the woman began arguing after she said she wanted to go home and that Henriquez allegedly attacked her. The woman jumped out of the car and flagged down a Northeastern University police officer in the area of 21 Forsyth St., police said.

The unidentified woman, who is in her 20s, told officers that Henriquez punched her while they were in the car, according to authorities. She received medical attention at the scene but refused further treatment, police said.

The relationship between Henriquez, a Democrat who represents the Fifth Suffolk District, and the woman was not immediately clear, but authorities believe she may be his girlfriend.

Henriquez, 35, could not be reached for comment on Sunday after he was bailed from a police precinct in the South End. There was no answer at his listed address in Dorchester, where two of his campaign signs were visible on the first-floor windows. Henriquez is scheduled to be arraigned Monday in Roxbury District Court, though he could instead be called to court at a later date, authorities said.

A full police report on the event will not be available until Monday, Officer Nicole Grant, a police spokeswoman, said Sunday night.

City Councilor Tito Jackson, whose district overlaps with Henriquez’s, was at the police station Sunday afternoon but did not provide the state representative any bail, Jackson spokeswoman Bennett Wilson said in a brief phone interview.

“Representative Carlos Henriquez has been a dedicated public servant and deserves due process in light of the very serious nature of these charges,” Jackson said in a written statement.

Other officials expressed surprise at the arrest.

“I thought it was very much out of character for Representative Henriquez, who I’ve come to know in the Legislature and think of as a very good person,” said State Representative Russell E. Holmes, a Mattapan Democrat, who like Henriquez is a first-term lawmaker.

Holmes said that he and Henriquez have worked together during the redistricting process and on efforts to improve a pending crime bill.

“I’ve never even heard him raise his voice,” Holmes said.

John Barros, executive director of the Dudley Street Neighborhood Initiative, a nonprofit serving Roxbury and Dorchester, said in an e-mail that Henriquez was president of the group’s board of directors from 2007 to 2011.

Barros said he was saddened by the news of Henriquez’s arrest. “The allegations are totally uncharacteristic of the behavior and values displayed by Representative Henriquez as a neighbor and during the time he served as a member of the board of directors for the Dudley Street Neighborhood Initiative,” Barros wrote.

On Saturday, Henriquez attended a large outdoor party on Wendover Street in Dorchester dubbed Project V, according to party organizers.

Organizer Valdir Rosario, 27, said Sunday that he threw the party to bring the Cape Verdean community together and had asked Henriquez for advice about permitting and other issues beforehand.

Rosario and his sister, Veronica, 30, said Henriquez briefly attended the party after 3 p.m. and was alone. They said food and alcohol were available at the party, but they did not see the lawmaker eating or drinking anything.

Veronica Rosario said Henriquez was “one of our supporters [and] he passed by just to say hi . . . He was here, he was professional, as you would expect a state rep to be.”

Henriquez discussed the party on Twitter.

“I stopped by #ProjectV to support my friends and community,” he tweeted Saturday. “It is a peaceful loving event. Thanks for the love.”

He later added, “crowd is leaving slowly but peacefully. [Boston police] and residents working well together!”

Henriquez serves on the Joint Committee on Education, the Joint Committee on Mental Health and Substance Abuse, and the Joint Committee on the Judiciary, according to his biography on the Legislature’s website. House rules allow for a lawmaker to be stripped of committee assignments upon indictment, but a spokesman for House Speaker Robert A. DeLeo declined to discuss possible sanctions.

“The allegations that have been raised are disturbing and troubling and should be taken very seriously,” DeLeo said in a statement. “The matter is now being handled by the appropriate authorities, and that process will play out.”

In May 2011, Henriquez hailed Governor Deval Patrick’s proposal to cut youth violence in the state.

“Youth violence is the result of adult failures in households, schools, prison systems, and other institutions,” Henriquez said.

Last summer, Henriquez got into a heated exchange with Boston police officers after they stopped a car in which he was riding, which did not have a front license plate. Henriquez said at the time that he questioned why so many officers were present and that in response to his complaints, one officer told him, “What’s it to you?” and, when he continued to inquire, another officer told the driver: “Your buddy has a lot of mouth.”

Henriquez said he complained about his treatment to a top police official. “I’m not looking for retribution or anything like that,” he said. “I just want to make sure the next citizen has a better chance at customer service.”

Police maintained they acted appropriately and that when they checked the car’s license plate number, they discovered that the owner was wanted on charges of felony assault. Police said the owner was the driver’s roommate and was not in the vehicle at the time.

Henriquez said he did not know the owner and was not aware that the man had an outstanding warrant.

Henriquez’s mother, Sandra B. Henriquez, has been assistant secretary for public and Indian housing in the US Department of Housing and Urban Development since June 2009.