He has already killed seven people and injured two others.
The killer has access to multiple cars which he uses to hunt down his victims before shooting them and driving off.
Most of the shootings have taken place at night as his victims were standing or sitting in a car outside a home.
Dubbed the Serial Street Shooter, the killer has been terrorising the US city of Phoenix for months.
Stalking predominantly Hispanic neighbourhoods, the gunman appears to strike at will and police have warned no one is safe.
His most recent killing was his most daring when three people were shot dead.
Angela Linner, Maleah Ellis, and Stefanie Ellis were killed in front of a home in the area of 6300 West Berkeley Rd on June 12.
The killings happened just 2km from where Krystal Annette White, 55, was discovered in the early-morning hours of April 19. Police believe she was the killer's second victim.
A BIG CLUE
Up until recently, few people could testify as to what the killer looked like, but then he slipped up and one witness got a good look at his face.
On July 11, a man who was with his four-year-old nephew had his car riddled with bullets at point blank range.
The bullet just missed the boy in the passenger seat before exiting the car door.
The 22-year-old victim told The Phoenix New Timesthat the gunman could clearly see his nephew in the car when they were shot near 30th Street and Thomas Road.
The man, who wants to remain anonymous, said it was a miracle they weren't hit.
The suspect driving a black, four-door BMW and described as a young-looking, clean-shaven Hispanic man with short black hair, pointed a black handgun and fired it at them.
The man ducked his head and covered his nephew's before speeding away.
"I was like, 'I gotta get away from this dude!'" he said. "It was so quick and so surprising."
But authorities fear the killer's victims won't be so lucky next time.
Police have had hundreds of leads since the shootings began in March, all of which have taken place around Phoenix, Arizona.
A previous reward leading to the killer's arrest has been upped from $50,000 to $75,000 as police face a race against time to find him.
The suspect, also known as the Maryvale Serial Killer, doesn't appear to discriminate, with young, old, men, women and children targeted.
Of the nine shootings in total, five have taken place in the suburb of Maryvale.
'SOMEONE KNOWS SOMETHING'
At a press conference on Thursday, Phoenix Police reassured the public that solving the Serial Street Shooter case remains a top priority and re-released a series of sketches to catch the killer.
City Police Chief Joe Yahner made a fresh appeal for information, saying someone out there knows something.
"We collectively know somebody out there has information about the suspect involved in these crimes, and we desperately need that information," he said.
"Someone out there knows who did this. We need our community to call us or Silent Witness and help us solve these cases, bring justice to these families and victims, and prevent more violence from occurring."
At a joint news conference with the mayor, the Arizona lawyer general and officials from the FBI and the US Marshal Service, authorities appealed for people to take precautions.
US Marshal David Gonzales said it was known that serial killers like to brag about the atrocities that they commit and he didn't think that this was any different.
'HE WILL STRIKE AGAIN'
It has been a more than a month since the last attack on July 11 and unlike other victims, the man who survived that shooting got a clearer glimpse of the suspect.
In a recently released police report, authorities said the victim came to rest at a stop sign at a four-way intersection when a black BMW made a right turn.
At that point, their cars were facing each other. The man told police he looked over at the other driver, who then pointed a handgun at him.
The driver fired once.
The victim said he immediately ducked and reached for his nephew. He heard more gunfire and sped away. He made it home, where he called police.
Investigators found three bullet holes on the victim's car, according to police records. They also recovered five shell casings from the intersection.
Police have canvassed the neighbourhood and obtained footage from surveillance cameras in businesses in the area.
Despite an overwhelming amount of physical evidence including ballistics, investigators said they believe their big break will come from the public.
Authorities have urged witnesses or victims fearful about their immigration status not to be afraid to come forward with any information they may have.
However police cannot confirm whether the killer himself is white or Hispanic.
-With Associated Press.