Authorities on Sunday announced arrests of men for two local murders.

The Boston Police Department reported arresting Marcus Ambroisio, 24, of Dorchester, on charges he fatally shot Gregory Phillips outside 155 Savannah Ave. in Mattapan around 10 p.m. on Dec. 10, 2018.

Police reported arresting Ambrosio around 3 p.m. Saturday on Theodore Street, off Morton Street, about 1 1/2 miles from where Phillips was shot.

At the time of the murder, police said a man fired a shot at Phillips, got into a maroon minivan with two other men, then fired several more shots before they drove off.

The Suffolk County District Attorney's office reported the arrest of William Sanchez, also known as Wilman Soto, for Jorge Medina's murder on Oct. 8, 1995, at a house party at 195 Norwell St. in Dorchester.

Finding and returning him Sanchez, now 46, to Boston to face charges would have proved impossible until 2015, when the US and the Dominican Republic signed an extradition treaty; it then took several more years to track him down and confirm his identity, the DA's office reports. He was flown back to Boston on Friday and is scheduled for arraignment in Suffolk Superior Court tomorrow, the DA's office reports.

The DA's office provided this account of Medina's murder: "An investigation revealed Mr. Medina had been serving as a bouncer for a house party at the address and that he had escorted Sanchez from the party. A few minutes after being ejected, Sanchez returned and fired at Medina and another person as Medina was attempting to return to the house. At the time of the murder, Sanchez, also known as Wilman Soto, had been living in Hyde Park. "

Medina had grown up in Jamaica Plain but was living in East Boston when he was murdered.

In a statement, DA Rachael Rollins praised the Department of Justice for getting Sanchez extradited and the US Marshals, assistant DA John Verner and Det. Jack Cronin of the Boston Police unsolved homicide unit for finding and returning him to Boston.