From the time Pamela Butler vanished from her two-story house in Northwest Washington just before Valentine’s Day 2009, police and her family believed that the 47-year-old had been killed, and all signs pointed to her boyfriend.

For eight years, police found no clues to support a criminal charge. A search of the victim’s home apparently turned up no blood. The scouring of a 6,000-acre park along the Potomac River came up empty. And despite extensive questioning of the boyfriend, he never wavered from his claim of innocence.

No body ever has been found, and she was declared dead by a judge in July 2016.

What police had, though, was surveillance video recorded on and around Feb. 12, 2009, from Butler’s house at Fourth and Oglethorpe streets NW. It only deepened the mystery.

“We saw them go inside together,” acting D.C. Police Chief Peter Newsham said. “He was seen leaving. She was never seen again.”

(The Washington Post)

[Woman’s disappearance leaves a trail with no end]

On Saturday, D.C. police announced a break in the cold case. They had arrested the boyfriend, Jose Angel Rodriguez-Cruz — who now is 51 and lives in Alexandria, Va. — and charged him with first-degree murder. He spent most of Saturday being questioned by detectives.

Rodriguez-Cruz is expected to make his initial appearance in D.C. Superior Court on Monday. In extensive interviews with The Washington Post in 2009, he denied any involvement in Butler’s demise.

“This was a woman I really cared for, okay,” he said then. “I mean, I treated her like a queen. . . . I’m telling you, there’s no way I would ever hurt her.”

Butler’s brother, Derrick Butler, who lives in Maryland and teaches at Frank W. Ballou Senior High School in Southeast Washington, described the family as “relieved, elated, all of the above.” He added: “It’s been a long time coming.”

Police declined to describe in detail what led to the arrest, but authorities noted that they were helped by a deep dive into the suspect’s history of domestic violence toward women before he met Pamela Butler.

The lead detective was Michael Fulton, a 28-year veteran assigned to the cold-case squad, whom Newsham said picked up the file two months ago.

“When he looked at the case with fresh eyes, he was able to determine additional information,” the chief said. “Piecing all that together with information that we had already collected, the detective was able to get a warrant.”

[Family sees clues in woman’s disappearance]

The case has been one of the police department’s most complex and frustrating cases, both because a suspect seemed so talkative with police and the media, and because of the dearth of physical evidence, including a body.

Now, prosecutors are faced with their first murder case that lacks a body since 2011, when four people were convicted in the killing of an 18-year-old woman who was lured to an apartment, beaten to death and thrown into a trash bin. Her body was thought to be lost in a landfill.

On Saturday, Mayor Muriel E. Bowser (D) joined Newsham and Derrick Butler outside police headquarters to announce an arrest that for years had baffled detectives and left a grieving family without answers.

“While this does not bring Ms. Butler back,” Bowser said, “We hope it will bring closure to her family and friends, and justice to us all.”

Derrick Butler, 54, said that he believes his sister was killed because she had told Rodriguez-Cruz she was breaking off their five-month relationship, which had started after the two met on the eHarmony.com dating service.

Friends described Pamela Butler, a computer specialist for the Environmental Protection Agency, as an accomplished, educated professional who was hypervigilant about her safety but who longed for someone to love. She owned a two-story, six-room house, along with a Mercedes and a Jaguar, and outfitted her Brightwood home with an unusual number of surveillance cameras.

Relatives scoured some of the video before police took it as evidence, but nothing indicated that Butler was in peril. She disappears from the frames after Feb. 12, 2009, but Rodriguez-Cruz is seen going in and out the following day. At one point, the family said in 2009, he is seen leaving the house with two shoulder-slung duffel bags and a plastic trash bag.

[Video — Family recalls missing woman]

It was not clear Saturday whether Rodriguez-Cruz has a lawyer. In 2009, he gave extensive interviews to The Post for reports on Butler’s disappearance. He had grown up in Puerto Rico and New York and joined the Army in 1982, at 17. He was a military police officer and a sergeant, but also had been demoted for having an affair with a fellow serviceman’s wife.

Rodriguez-Cruz told The Post that he had been diagnosed with post-traumatic stress disorder after serving with military advisers in Latin America and helping combat insurgents. He worked as a security guard but said he could not hold a regular job because of his nerves and “crushing migraine” headaches. He blamed “mental issues” for domestic problems and cited an ex-wife who he said “falsely accused” him of abuse. He said that a former girlfriend stabbed him in the stomach during a fight.

Rodriguez-Cruz said that he started working as an office manager at a drug rehabilitation center in 2008 in Annandale and signed up with eHarmony to restart his life.

Through that site, he met Butler — who was divorced. They met for their first date at a Cuban restaurant. Asked why the computer matched them, Rodriguez-Cruz had cited eHarmony’s “29 dimensions of compatibility,” saying that he and Butler agreed on the most important qualities in a relationship — “trust, communication, physical affection” — and had common likes and dislikes. Both were orderly. He told her about his problems in the military.

The Post reported that after the 2008 recession, Butler was feeling financial stress. Tension mounted and apparently came to a head the night of Feb. 12, 2009, a Thursday, the last time Butler was seen — captured on her own surveillance video walking into her home.

Rodriguez-Cruz told The Post in 2009 that Butler ended the relationship the following day. She wasn’t seen again, police said. After Butler didn’t show up for a family dinner on Feb. 17, Butler’s mother went to police.

“From the outset of this case, we thought the circumstances were very suspicious,” Newsham said.

Police interviewed Rodriguez-Cruz extensively, putting so much pressure on him that he complained to The Post that detectives “made my life hell.” Police found no clues in the home — Butler’s nephew said that police found no blood — and a search for her body in the expansive Seneca Creek State Park along the Potomac River in Montgomery County, Md., came up empty.

Derrick Butler described the past years as agony. “All we could do was wake up in the morning and wonder, is this going to be the day? Is this going to be the day?” he said. “It’s been a roller-coaster ride that never ends. You would never want to see a family go through this.”

Keith L. Alexander and Paul Duggan contributed to this report.