Two men were arrested and charged with murder for last month's shooting of a recent college graduate who was hit by a stray bullet while sitting in a car outside a late night party, the Suffolk County District Attorney said.

Manuel Andrade, 34, of Boston's Dorchester neighborhood, and Casimiro Barros, 21, of the Roxbury neighborhood, began shooting at each other outside an after-hours party in Dorchester on March 24, where Chiara Levin, 22, was struck, District Attorney Dan Conley said at press conference Saturday.

A police investigation found that Levin and two friends had just met Andrade at a downtown bar that night and one of the accused gunmen drove them to the party in his black Cadillac Escalade.

Andrade scuffled with an unknown man inside the party and shot him, Conley said. Then he left the party with Levin and her friends who were waiting inside the Escalade when he began exchanging bullets with Barros.

Levin was killed by a single gunshot to the head and died at nearby hospital later that night.

Conley said investigators did not determine who fired the shot that killed Levin, but Massachusetts law holds both men responsible for her death.

Levin, a recent graduate of the University of Michigan, was a Danville, Ky., native who recently moved to New York City to take a job as a booking agent. She was visiting Boston for a family celebration.

Andrade and Barros will be arraigned Monday in Dorchester District Court, Conley said.

Police Commissioner Ed Davis said witnesses at the party were cooperative with police — a departure from many unsolved murder cases in Dorchester and other inner-city neighborhoods where officers say bystanders often refuse to speak.

Levin's family, parents Bill and Grazia Levin and younger sister Elena, released a statement Saturday in response to the arrests, the Danville Advocate-Messenger reported.

"We continue to mourn the senseless loss of our dear Chiara," they said in the statement. "She is constantly in our thoughts and always in our hearts. We wish to express our gratitude to members of the Boston Police Department working on our behalf and that of all law-abiding citizens of the community as well as to those persons who have aided them in their efforts."

"While the recent arrests cannot bring Chiara back to us, we are pleased that the investigative and judicial processes are taking their course, and we will continue to monitor closely all matters and events pertaining to the case," according to the statement.