A series of shootings that left 13 people wounded over the past two months may be linked to earlier shootings that left four people dead, police said Tuesday.

Police spokesman Andy Hill said investigators connected the two sets of crimes after discovering new information. He declined to elaborate.

"We believed this possibility existed all along," Hill said.

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Detectives have been tracking the 13 shootings, which began May 2, as part of an unusual crime wave in Phoenix. Police said they believe the recent shootings are related to 25 connected shootings that began in May 2005 and killed at least four people. Horses and dogs have also been shot.

The 13 latest shootings all happened late in the evening or early in the morning. Most occurred on major roads in Phoenix, wounding people as they walked down the street or rode bicycles. No one was killed.

Since August, a task force has also been trying to catch a serial killer dubbed the Baseline Rapist who they believe is responsible for five killings and a series of rapes and assaults.

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