One man was killed and three others wounded within a span of 90 minutes in separate shootings in Mattapan and Dorchester last night into early this morning.

Boston Police Officer Rachel McGuire said dozens of witnesses at a family barbecue on Astoria Street in Mattapan were placed on MBTA buses and taken to the department's homicide headquarters after a 31-year-old male was murdered at the party at approximately 11 p.m.

A second shooting victim from the same event was found near by. His injuries are not life-threatening, McGuire said.

Thirty minutes later, a third man was found shot at Norfolk and Elizabeth streets in Dorchester. McGuire said he is expected to survive, as well.

Then, at 12:30 a.m., a fourth man was found shot on Fowler Street in Dorchester, also with non-life-threatening injuries.

As for whether there is any connection between the three shooting scenes, McGuire said, "It's under investigation at this time."