Nearly three years after a 31-year-old Butler Area High School graduate went missing in Southern California, police have arrested his alleged killer.

Long Beach police Monday announced that Scott David Leo, 54, has been charged with the 2017 murder of Zachary “Zach” Kennedy.

Leo, of Long Beach, is being held in the Long Beach City Jail in lieu of $2 million bond. Police said he was arrested at his home, where authorities say Kennedy's remains were unearthed in 2018.

A telephone call around 6 p.m. Monday from the homicide detective working the case is how Kennedy's father, Jeffrey Kennedy, formerly of Butler Township, learned of the arrest.

It was the news he had been waiting for years to hear.

“It was pure relief,” Jeffrey Kennedy, who moved to Florida in January, said Tuesday. “I just felt a ton of weight was lifted off my shoulders. I got emotional for a little bit. It brought a tear to my eye.

“I was able to talk to the detective and work through all that. Once I hung up, then I had to have my time for myself.”

Other family members were also happy with the news.

“We're very glad they finally arrested someone,” Kennedy's grandmother, Brenda Minto of Butler, said Tuesday. “We've suspected for a long time who did it, and I hope he spends the rest of his life in jail.”

Police took to social media to report the arrest, identifying Leo as being “responsible” for Kennedy's death, but admitted that their investigation is not finished.

“Kennedy and Leo had a personal relationship, and detectives are continuing to investigate a possible motive,” according to a post on the department's Facebook page, “but we believe this to be an isolated incident.”

Police said that after “relentless follow-up in Kennedy's disappearance,” homicide detectives learned the victim was last seen at the defendant's home in October 2017.

Detectives in May 2018 went to Leo's home with a search warrant to excavate the property, where human remains were dug up. The Los Angeles County Coroner's Office later identified the remains as those of Kennedy.

Jeffrey Kennedy said his son's body had been wrapped in plastic and placed in a large storage container. The container was covered by cement before being buried.

The investigation has not pinpointed how Kennedy died. On the death certificate, Jeffrey Kennedy said, the cause of death is listed as “undetermined.”

Citing court documents, specifically the search warrants obtained during the police investigation, the Long Beach Post reported Tuesday that authorities believe Kennedy visited Leo on the night of Oct. 22, 2017, where one witness said they engaged in sexual activities.

The Post said that later that night, according to detectives, Leo started texting another man saying Kennedy was overdosing on the so-called “date-rape drug” GHB.

Jeffrey Kennedy acknowledged that his son struggled with drug use and was HIV positive.

In one text, the Post reported, Leo allegedly sent a photo of the victim with his face resting against the side of a bathtub, possibly unconscious or already dead.

According to detectives' account, the Post said, the defendant texted that he couldn't find a pulse for a while, but that Kennedy later “popped up like nothing happened.”

Investigators said nobody saw Kennedy after that night, according to the Post.

While he has remained in regular contact with the detective and the assistant district attorney assigned to his son's case, Jeffrey Kennedy said certain details about the investigation have not been shared with him.

In April, he and his ex-wife, Kathleen Minto-Iarrapino of Butler, Zachary Kennedy's mother, along with Kennedy's only biological sibling, Ashley Kennedy of Butler, filed a wrongful death lawsuit in Los Angeles Superior Court, naming Leo as the defendant.

They allege in court papers that Leo neglected to help their son after he overdosed.

According to the lawsuit, “As (Kennedy) was fighting for his life in (Leo's) bathtub, Leo text(ed) a photo of (Kennedy) to his friend, yet failed to call 911 or attempt to render any assistance, resulting in Zachary Kennedy's death.”

After Kennedy turned up missing, the suit alleges, his family “searched in vain for their beloved son and brother for many months” and that “through their devotion and the dedication of law enforcement, they found the buried remains of their beloved Zachary Kennedy in defendant Scott Leo's backyard.”

The suit further alleges that Leo “handled, desecrated and hid (Kennedy's) human remains in his own yard at his own residence.”

Money is not the motive for the lawsuit, Jeffrey Kennedy said.

“We're doing this because we want justice for Zachary,” he said. “Scott Leo needs to pay for his crime either criminally or civilly, or even both.”

A Butler native, Kennedy attended Knoch High School until he turned 16, and opted to live with his father in the Butler area. While attending Butler Area High School, he was a member of the swimming and diving team.

He graduated in 2004, and briefly attended Slippery Rock University. Later, his family said, Kennedy worked as a server at the Ginger Hill Tavern restaurant and bar in Slippery Rock and as a cashier at Sam's Club in Butler Township.

In 2008, he followed a female friend to California.

Word that his son's alleged killer was arrested and is behind bars stirs mixed emotions for Jeffrey Kennedy.

“I had severe depression because of the death,” he said. “I still suffer from depression, but it's not as severe now. I'll never have Zachary back, but at least now I can move on and close that door and go through the next step in the grieving process.

“No one should ever have to die the way Zach died, and no family should have to ever go through what we had to go through.”