updated 01/22/2014 AT 2:00 PM ET
•originally published 01/22/2014 AT 6:20 PM ET
When the body of pregnant Brittany Royal was found in the waters off the coast of Hawaii’s Big Island last May, her boyfriend Boaz “Bo” Johnson went missing and immediately became the chief suspect in her strangulation murder.
But a search for Johnson, 22, came up empty. Then strange anonymous signs posted on trees and a handwritten note to a local newspaper suggested he, too, was murdered in a business dispute.
“If he isn’t the murderer, that means he’s dead,” his sister, Sarah Johnson, told PEOPLE shortly before the holidays. “So what do we have to look forward to?”
This week the Johnson family’s worst fears were realized. On Tuesday, police announced that remains found on Jan. 2 about two miles from the apparent murder scene on a lava field southeast of Hilo were positively identified through DNA as Johnson.
The body was found hanging from the same kind of rope used to strangle Royal, police say. Nearby was a notebook with a suicide message written in what investigators determined to be his hand.
“He confessed to strangling Brittany while in a domestic dispute and to throwing her body in the ocean,” Hilo police Assistant Chief Henry Tavares said during a news conference. “He also indicated his intent to end his own life.”
Royal, 25, a free spirit from Tustin, Calif., who frequently traveled on her own, met Johnson, from a large family in Petersburg, Alaska, when they both were visiting Hawaii in January of 2013. They began living together and last April and in May traveled to see their respective families to tell them Royal was pregnant.
Johnson had plans to purchase land for an organic farm and to possibly operate tours of the lava fields, family members said. But shortly after they returned to Hawaii last May, Royal’s body was found and Johnson went missing.
For months, Royal’s family didn’t know what to think about the young man they had just met. Now two families are coping with losses.
“We have our healing to do and they have their healing to do,” Royal’s mother, Julie Royal, told PEOPLE on Wednesday. “I look at our situation and it’s bad. Theirs is doubly bad. Not only is their son dead. He’s a murderer.”