Phoenix serial killer
Phoenix police have urged residents to remain vigilant as the search for a suspected serial killer continues.Phoenix Police

Phoenix police have connected a ninth shooting attack to a serial killer on the loose, who was last believed to have struck in mid-June when he fatally shot two women and a 12-year-old girl. Investigators have added a 11 July incident where a man and a 4-year-old boy sitting in a vehicle where shot at, to the string of crimes committed by the suspect.

"The threat is still alive," Phoenix Police Sergeant Jonathan Howard said on 3 August. "We don't want to see anybody else get hurt. We want to make an arrest and stop this. We're fortunate in this new incident that nobody was injured."

Howard added: "If there can be a benefit to something like this, it's that we did obtain additional evidence." He added that with the help of witness statements, detectives have come to believe that the suspect has access to several vehicles. The vehicles have been described as a white Cadillac or Lincoln and a late '90s or early 2000s 5 series BMW.

The police sergeant told reporters that investigators are looking into whether the suspect works as a mechanic or on a used car lot, NBC News reported. Howard said that investigators are also "pretty confident" they have uncovered all related incidents.

Investigators have found that in each incident, the suspect attacked his victims near their vehicle or at home, in the evening or early morning hours, in the working-class neighbourhood of Maryvale. NBC News reported that there is physical evidence tying all nine shootings.

The incidents date back to 17 March, when a 16-year-old boy was wounded. Seven people have been killed since the shootings started. The victims have been identified as: 21-year-old Diego Verdugo-Sanchez; 55-year-old Krystal Annette White; 32-year-old Horacio Pena; 19-year-old Manuel Castro Garcia; 33-year-old Stefanie Ellis; 12-year-old Maleah Ellis; and 31-year-old Angela Linner.

Phoenix shooting victims
From left, clockwise: Krystal White, Maleah Ellis, Stefanie Ellis, Diego Verdugo-Sanchez, Manuel Castro Garcia, Horacio De Jesus Pena, Angela LinnerHandouts

The FBI is offering a $50,000 reward for information leading to the suspect's arrest, Fox News reported.