Police are investigating four shootings in Dorchester and Mattapan, two of which sent people to the hospital with life-threatening injuries.

Around 11 p.m. on Saturday, a 16-year-old and a 23-year-old were found shot outside 2 Page St. The older victim was taken to a local hospital with life-threatening injuries; the teen is expected to survive.

Around 10 p.m. on Sunday, a man was found shot in the neck on Willmore Street in Mattapan. Police are looking for a black male riding a black moped and wearing a gray hoodie.

About 40 minutes later, police responded to Astoria Street - just a few blocks away, on a report that two men walked up to a house and opened fire.

Then, about 20 minutes after that, police found a man in a backyard of a Norfolk Street house - behind an Astoria Street house - suffering from a gunshot wound to the stomach.

Because of the severity of his injuries, the homicide unit was called in, just in case.

The two suspects are described as black. One was wearing a Red Sox hat, a sleeveless denim vest and tan cargo pants.