Detectives identified a 15-year-old as one of the attackers and arrested the young man at 10:30 a.m. in Watsonville. He was booked into juvenile hall on charges of assault with a deadly weapon and robbery.
The Santa Cruz Sheriff's Office is asking for the public's help in finding the other suspects responsible for the gruesome attack on Memorial Day in Aptos.
Several masked suspects entered a garage in the 100-block of Monte Vista Drive around 1:40 a.m. and assaulted three teenage boys with a hammer while two of them were sleeping, according to the Sheriff's Office.
[Ads /]
"We live in such a quiet neighborhood. It was absolutely shocking," said neighbor Patrick McMenamy.
The victims, two 16-years-old and one 17, all suffered head injuries during the attack. The 17-year-old, an Aptos High School student named Alex, was taken to a trauma center and is now in stable condition.
RELATED: Santa Cruz Sheriff's Office searching for suspects in Aptos hammer attack
"This assault was beyond stupid and these suspects are fortunate nobody is dead as a result of this attack. Our deputies are going to find every one of the suspects, they should turn themselves in now," Santa Cruz Sheriff Jim Hart said.
Detectives say the suspects stole several items after the assault and then fled the scene in an unknown vehicle. They could only be described as men between the ages of 18 and 20.
Crime scene investigators have processed the home for forensic evidence. The neighborhood was also canvassed for surveillance video that detectives hope may have captured the suspects' vehicle leaving the scene.
[Ads /]
The Sheriff's Office believes the attack was targeted, but the motive remains unclear.
A GoFundMe page has been set up to help the family with medical expenses.
If you have any information that could help authorities with this case, you're asked to call Sgt. Dee Baldwin at (831) 454-7635.
ABC7 News reporter Chris Nguyen contributed to this story.