The gunman fired at a man and a 4-year-old boy sitting in a car on July 11

Credit: Phoenix PD

Arizona police thought the shooting spree of a suspected serial killer ended with the June slayings of a mother and her 12-year-old daughter.

But officials have now tied a ninth, non-fatal attack to the gunman, who has killed seven people seemingly at random across Phoenix since March, police announced.

On July 11, a gunman opened fire on a man, 21, and a 4-year-old boy as they sat in a car, the Phoenix Police Department announced in a statement. The man and boy were not injured in the shooting.

The names of the man and boy have not been released.

Seven people have been killed and two more wounded in a series of attacks police believe to be connected.

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Police have few leads and are relying on the public to identify the shooter, described as a thin man in his 20s, according to the AP.

“Investigators believe that the suspect has access to multiple vehicles which may change but the two best described are a white Cadillac or Lincoln type vehicle and a black late 90’s or early 2000’s 5 series BMW,” the police statement said.

Authorities have offered a $50,000 reward for information leading to an arrest – more than double the $20,000 originally offered.

“The threat is still alive,” Phoenix Police Sgt. Jonathan Howard said, according to NBC News. “We don’t want to see anybody else get hurt.

He added: “We want to make an arrest and stop this. We’re fortunate in this new incident that nobody was injured.”

Three of the murders linked to the suspected killer were the June 12 slayings of 12-year-old Maleah Ellis, her mom Stefanie and family friend Angela Linner as they sat in a car and listened to music outside their Maryvale home. The shooter pulled up alongside the car and opened fire, shooting the victims more than 30 times. Maleah is the killer’s youngest murder victim.

Stefanie’s brother and Maleah’s uncle, Sylvester Ellis, opened up to PEOPLE about the moment he found his sister and niece dead.

“The gunshots woke me up … I’m the one that actually found them in the car. And life hasn’t been the same,” the 35-year-old said. “I woke up out my sleep, went outside and saw them like that … they were all slumped over in the car.”

Other murder victims include Diego Verdugo-Sanchez, Krystal White, Horacio De Jesus Pena, Manuel Castro Garcia.

The crime spree began on March 17, with the non-fatal shooting of a 16-year-old boy as he walked down the street.