West African immigrant Bampumim Teixeira:
http://www.wbur.org/news/2017/05/06/south-boston-condo-double-homicide
The two doctors were found dead in their secure penthouse with their hands bound and throats slashed, as Mr Teixeira was leaving their building with a gun – which he fired at police responding to a 911 call

Why file suit for malpractice when you can simply murder the doctors?
Creepy – very creepy.
A few additional thoughts – the man was working for a pain management clinic, which makes him a magnet for people with opiate addictions.
The penthouse is accessed only by a keycard, and the elevator won’t go to their floor without it. My theory is that after he murdered them, the killer was unable to call the elevator to leave because he didn’t know how to do it or the system had to be unlocked to exit. That would explain why he was still there when the police arrived.
The penthouse seems a bit expensive for a doctor whose practice involves prescribing pain mecication.
The building owner has confirmed that the alleged killer worked for the building as a concierge. When he was caught, he had a bag of women’s jewelry in his possession