BOSTON (CBS/AP) — Testimony is underway in the trial of a man accused of killing two engaged doctors in their luxury South Boston condominium. Bampumim Teixeira, 32, of Chelsea, is charged with stabbing Dr. Lina Bolanos and Dr. Richard Field to death in their home in the Macallen Building on May 5, 2017.

Dr. Richard Field and Dr. Lina Bolanos (WBZ-TV)

Prosecutors believe robbery was the motive. They claim Teixeira knew the layout of the building because he was a security guard there briefly in 2016. Police recovered a carving knife in the apartment as well as a bag containing Bolanos’ jewelry.

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“The evidence will show over the course of the next couple weeks, ladies and gentleman, that these murders were committed by one person acting alone. One person with a purpose and a plan,” prosecutor John Pappas told the jury in opening statements Thursday morning.

Teixeira has pleaded not guilty to two counts each of first-degree murder, armed robbery, and kidnapping, and one count of armed home invasion.

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“No credible evidence will tell you that Bampumim Teixeira broke into the home of Lina Bolanos and Richard Field and murdered them on May 5th of 2017,” defense attorney Steven Sack said in his opening statement.

Bampumim Teixeira in Suffolk Superior Court November 21, 2019. (WBZ-TV)

Field’s brother Jason was the first to take the witness stand Thursday. He was followed by an interior designer, who was doing work on the couple’s condo. Joseph Russell, a carpenter who was also doing work on the condo, was the third witness to testify.

Bolanos, 38, was a pediatric anesthesiologist at Massachusetts Eye and Ear. Field, 49, was an anesthesiologist at North Shore Pain Management.

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Their families have also filed a wrongful death civil lawsuit against the building’s owners claiming security there was weak.