AUBURN, Maine — A Lewiston man was sentenced Friday to 55 years in prison in the 2011 slaying of 22-year-old Christiana Fesmire.

Buddy Robinson, 32, was convicted of murder at trial in Androscoggin County Superior Court nearly a year ago. Fesmire’s remains weren’t recovered until two months later.

Fesmire disappeared on July 1, 2011; Robinson was arrested and charged with her murder more than three months after.

Fesmire rented a first-floor apartment in a building at 36 Highland Avenue; Robinson lived upstairs with his sister, Brandi, and her young son.

Prosecutors presented nearly six days of circumstantial evidence that painted a picture of a an angry Robinson who “snapped” on the morning of July 1, 2011, and killed Fesmire. He fought with her in her apartment from which she had been moving that morning. Her head smashed against the side of the bathtub, then he drowned her in the tub by sitting on her.

“She died hard,” Robinson had told witnesses who testified.

He wrapped her body in a comforter and stuffed her in the trunk of a black Lexus sedan parked in the garage.

Robinson called his sister, Brandi, using Fesmire’s cellphone at about 8:30 a.m. to tell his sister he had fought with Fesmire, prosecutors showed.

He mopped up the bloody evidence of his crime and waited for his sister to return to their upstairs apartment at the Highland Avenue building, according to police.

Despite several police searches, Fesmire’s body hadn’t been found by the time he went on trial.

Assistant Attorney General Andrew Benson said after the verdict that he had worried about his witnesses, many of whom had been granted immunity from prosecution for crimes including prostitution, drugs and perjury.

But Robinson had incriminated himself to a Lewiston police detective and to a Maine Army National Guard soldier with whom he had served.

He told Lewiston Police Detective Roland Godbout that he couldn’t remember where he put Fesmire’s body. To Rebecca Cornell du Houx, who is a mental health case worker, he sent text messages saying he hurt a woman “badly” and, “She’s dead.”

Their testimony corroborated the statements made by less credible witnesses, including a man who occupied the same prison cell pod as Robinson. That man, awaiting trial on a drug charge, said Robinson had confessed to killing a woman.

Benson said it was “very unusual” to prosecute a murder case when no body had been recovered to link the defendant to the victim.

But because Fesmire’s blood had been found in her apartment where she’d been killed as well as in the back of the car in which her body was transported, the court was satisfied the state had proved a crime had been committed, he said.

Defense attorney Edward “Ted” Dilworth sought to present at trial Robinson’s sister, Brandi, as an alternative suspect.

He told the jury that she had more motive than her brother to kill Fesmire. Brandi Robinson had hired Fesmire to work for her as an escort and held some of her earnings from that business.

The two had argued and once had a physical altercation at a hotel outside Boston. Dilworth had hoped to plant seeds of doubt in the minds of jurors by diverting attention from Buddy’s actions to his sister’s.

In his closing arguments, Dilworth claimed his client was “wrongfully accused of a crime he did not commit.” He said the case was “full of doubt,” especially the testimony of Brandi Robinson who, Dilworth said, never made eye contact with any juror.

But Benson downplayed Brandi Robinson’s role in the crime. During his hour-long closing arguments Friday morning, he said Dilworth “would have you believe Mr. Robinson is the victim of some sort of vast conspiracy, a conspiracy that must be . . . instigated by his sister.” Benson said she must be the “arch criminal, an absolute criminal genius . . . who was so cunning that she wove a cunning web in order to ensnare her brother” and enlisted many others, including a Lewiston police detective.

“In the ultimate feat of cunning, she must have somehow arranged to have her brother . . . send a series of text messages on the evening of July 1 at the very time that Buddy is almost certainly out driving around scouting out locations . . . to dispose of Christiana Fesmire’s body.”

That was the same car that Fesmire was supposed to have borrowed from Brandi Robinson the morning Fesmire was killed to drive to a family reunion in Rangeley.

Moreover, Benson said Brandi Robinson tried to cover for Buddy and didn’t tell police what she knew for months in an effort to keep him out of trouble. That doesn’t fit with Dilworth’s theory that she was the mastermind, Benson said.

The most convincing evidence came down to opportunity, Benson said. Brandi Robinson had alibis all day long on July 1, 2011. She never had time to kill Fesmire that day, unlike Buddy, Benson said.