(CNN) The man accused of brutally killing two Boston doctors in their penthouse killed one doctor in self-defense and stole from the home but did not commit murder, his attorney said in closing arguments before a jury began deliberating the case Monday.

Bampumim Teixeira, a 33-year-old who had worked as a concierge in the building, is accused of fatally stabbing 39-year-old Lina Bolanos and her 48-year-old fiancé Richard Field, both well-known anesthesiologists, and leaving them in pools of blood at their Boston penthouse in May 2017. He has pleaded not guilty.

A day after the killings, Teixeira told police he was having an affair with Bolanos and killed Field in self-defense, according to a recording played in court. His defense team rested its case Friday without presenting any evidence, and Teixeira's account was contradicted by other evidence at trial.

The clip of Teixeira's recording was part of the evidence the prosecution presented before resting its case last week. Suffolk County Assistant District Attorney John Pappas questioned more than a dozen witnesses during the trial, including the couple's family and friends, first responders and investigators.

In closing arguments, defense attorney Steve Sack questioned the credibility and accuracy of the police investigation. He argued that Teixeira is not guilty of home invasion or kidnapping because Bolanos let him into the penthouse apartment.

"Sometimes the truth is the hardest thing to believe," Sack told the jury.

But prosecutors countered that the evidence against him was "overwhelming" and "damning" and said his interview with police was "imagined."

"We've gone beyond the preposterous. We're now existing in the theater of the absurd," Pappas said.

Couple sustained injuries from being bound or cuffed

Pappas told the court during his opening statement Field's hands were bound behind his back and he, like Bolanos, was found in a pool of blood.

On Thursday, medical examiner Richard Atkinson testified Bolanos had sustained 24 incised and sharp-force stab wounds. The autopsy showed Bolanos suffered multiple blunt force injuries, including significant injuries to her face and head, according to Atkinson. Field suffered a single fatal stab wound to the neck that severed his carotid artery, Atkinson said.

The couple also sustained injuries consistent with being bound or cuffed, he testified.

During cross-examination, the medical examiner said he was unable to determine who died first or the time of death. He said he could not tell what kind of knife was used.

Teixeira said he was having an affair with one doctor

Prosecutors claimed Teixeira briefly worked as a concierge for the building in which the doctors lived and during that time, became familiar with the building's layout.

In the recording of his statement to police, Teixeira said he began having an affair with Bolanos around that time. On May 5, he said Field found him with Bolanos — and then stabbed his fiancée to death.

Bampumim Teixeira

"He stabbed her right in front of me," said Teixeira, adding that he feared for his life. "It was either me or him."

Teixeira told police he did not have sex with Bolanos that day but had in the past. He claimed Bolanos told him Field was abusive.

"I'm not sorry," Teixeira said in the recording about killing Field. "A jealous man is the worst thing ever ... What I saw with my eyes was crazy."

There has been no evidence presented to support the defendant's account, which has been contradicted by the evidence at trial.

The victims tried to get help

Before they died, friends of the couple and a 911 dispatcher testified the doctors tried alerting authorities.

A chilling 911 call captured Bolanos' voice, according to testimony from her godmother.

In the call, Bolanos' voice came out muffled. And when she was unable to respond to repeated questions, the operator said she was "releasing the call" and hung up, CNN affiliate WCVB reported

Field also tried to get help, calling 911 eight times, Boston police Sgt. Scott Mackie testified, according to CNN affiliate WHDH. His phone log showed the calls lasted no longer than two seconds, Mackie testified.

The day of the killings, a friend of Field received text messages from him. Matthias Heidenreich testified he had received a series of texts from Field's phone which asked him to call 911 because an armed man was in the doctor's home.

Under cross examination in the last days of trial, Boston police Sgt. Det. Michael Devane told Sack he couldn't be sure who had sent those texts at the time of the crime because Bolanos made a 911 call from the doctor's cell.

A chilling message was scribbled on the wall

When police arrived at the apartment, officers testified they found Teixeira inside and shot him, thinking he had a gun.

On the walls of the penthouse, the words "payback" and "he killed my wife," were written out in large letters, Boston police Sgt. Edward Meade testified, according to CNN affiliate WHDH.

Jurors saw what officers found on the walls of the crime scene

Meade said officers found photos that were crossed out and marked.

Teixeira was arrested in the building's hallway, where he told police there were bodies inside the penthouse, Boston police Det. Sean Wallace testified.

"Then he said, 'You guys are going to die.' Then he said, 'They killed my wife.' Then he mentioned something, and I heard the word 'sniper,''' the detective told the jury.

In his statement to police, Teixeira said he told the officers, "Kill me now."

He said he had "no idea" about writing found on a wall of the apartment.