Boston Police Commissioner Kathleen M. O'Toole appealed for the public's help in tracking down violent criminals yesterday, in response to a spate of shootings in the city that left two men dead and three wounded.
''We're not going to get discouraged," she said. ''We need help from the community out there. . . . The slightest bit of information could really be helpful to us."
The slayings Friday night in Dorchester and Mattapan brought the number of homicides in Boston to six in 2006, compared with four this time a year ago. Last year was the deadliest year in the city in a decade.
The three nonfatal shootings brought the number to 36 so far this year, compared with 17 nonfatal shootings this time last year, according to police.
Responding to reporters' questions about the most recent rash of violence, at a news conference originally called to discuss snowstorm preparations, O'Toole said that police had made nine arrests involving gun charges in the 24 hours following the shootings and that detectives were working hard to solve the crimes.
As investigators scoured the city for leads, Daniel Brito mourned the death of his younger brother, Heriberto Brito, 23, who was gunned down shortly before 9 p.m. Friday at the intersection of Magnolia and Quincy streets in Dorchester.
''We don't know what happened. Nobody knows what happened," Daniel Brito said, his eyes welling with tears as he looked at traces of his brother's blood still visible in the street yesterday afternoon. In his hands, he clutched T-shirts he had designed earlier that day bearing his brother's smiling face and emblazoned with the words ''Gone But Never Forgotten."
Heriberto Brito's body was found by police responding to a call that a man had been shot at 8:53 p.m., authorities said. He was shot once in the upper chest, near the apartment on Quincy Street where he sometimes lived with his mother, according to relatives.
Family and friends gathered at the apartment yesterday. Daniel Brito said that his brother had been in trouble with the police in the past, but that the birth of his daughter a year and a half ago changed him. He was looking for a job and spent a lot of time alone, composing rap lyrics on his computer.
''He was trying to straighten out," Daniel Brito said, adding that his brother had been at the mall earlier on the day he was killed, buying earrings for his daughter.
Residents in the apartment building where Brito lived say the sound of gunshots is common at night. Usually no one is hurt, said resident Michael Hill.
''They act like cowboys from time to time," he said, referring to the shooters. ''You never see them; you just hear the shots."
Police were called about the first fatal shooting at 7:38 p.m. in a vacant lot on Hollingsworth Street in Mattapan. The 37-year-old male victim, whom police did not publicly identify, was pronounced dead at Boston Medical Center.
Residents said yesterday that the man was married and had young children and that he was shot in a vacant lot between two homes. The neighbors, who asked not to be identified, also said they saw a blue car speed away from the scene after the shots were heard.
Three police officers leaving a home a short distance from the vacant lot where the man was killed declined to comment on their investigation, but did say that the victim's family was ''distraught."
At just before 9 that night, more shots rang out in Dorchester, police said.
A 20-year-old Dorchester man told investigators that he was driving a rented car on Sawyer Avenue when someone starting shooting at him and his passenger.
The man managed to drive the car to Pleasant Street, where the car stalled and he and his passenger fled on foot, said Office John Boyle, a Boston police spokesman.
After finding someone to pick them up and drive them to Boston Medical Center, the driver was treated for a laceration to the right side of his head, and the 23-year-old passenger received care for a gunshot wound in his back, Boyle said.
Shortly before 11 p.m. Friday, a 17-year-old male was shot in the right arm while walking near the intersection of Washington and Eldon streets in Dorchester, Boyle said.
The victim told police that as he and a friend were talking, they noticed a suspicious-looking vehicle circling the neighborhood. Soon after that, a man dressed in black came running toward them.
He shot at the pair, but only the 17-year-old was hit, Boyle said.
In the late 1990s, Boston was hailed for its success in halting violent crimes. As part of the ''Boston Miracle," homicides in the city dropped 77 percent from 1990 to 1997.
But since then, the crime rate has been climbing; 2005 was the city's deadliest year in a decade, with 75 homicides.
Russell Nichols of the Globe staff contributed to this article.Christine McConville can be reached at email@example.com.