Thirty-eight shootings in the Phoenix area over the past 15 months are the work of a lone serial gunman and not two separate individuals, as investigators previously thought, police said Tuesday.
Thirteen people have been wounded in the last two months, and police have now linked the crimes to an earlier series of 25 shootings that left four dead.
"We believe the two series of shootings are related," Det. Stacie Derge of the Phoenix Police Department told ABC News. "We are treating them as one case rather than two."
Derge added that the person responsible was shooting from a vehicle, and people should exercise increased caution when walking by the roadside.
The first series of shootings began in May 2005, and there was a lull before the recent rash of shootings, which led police to believe that the two cases were unrelated. Police would not elaborate on what the new information was that connected the two crime sprees.
The shootings aren't the only serial crimes troubling police in the Phoenix area, though. Since August, investigators there have also tried to catch a serial killer dubbed the "Baseline Rapist," whom they believe is behind five murders and seven rapes.
"This started with robbery and sexual assault, and we now have five victims of homicide definitely related to him," Derge said. The detective added, though, that police do not believe the Baseline Rapist is linked in any way to the shootings.
With police saying there are two serial criminals on the loose, many Phoenix residents live in fear.
"Everyone is apprehensive," said Susan Thompson-McHugh, president of the Bel Air Neighborhood Association. "Women I know are thinking twice about going out by themselves, not just in the dark but also during the day."
Even police have been taken aback by the nature of the crimes.
"In the 25 years I have lived here, we have not had a situation where we have had two serial criminals at the same time in the city of Phoenix," said Derge.