Miami police investigate drive-by shootings that left one dead, seven injured.(Knight Ridder Newspapers)

MIAMI _ The morning after two drive-by shootings left a 13-year-old boy dead and seven teenagers wounded, detectives from several agencies sought clues linking them to a recent rash of ambushes in North Miami-Dade County.

The police have their work cut out for them: Few survivors are saying much. Most area residents, terrified of retaliation, are equally uncooperative.

Detectives suspect the July Fourth mayhem is connected to a simmering gang feud that has claimed at least 10 lives and left a dozen wounded in the last four months.

Many of those shootings involve teenagers of Haitian descent. They have been centered in an area east of Interstate 95 that includes North Miami, North Miami Beach and …