A British-born doctor and his anaesthetist fiance were murdered inside their US home shortly after he texted there was "a gunman in the house", according to reports.

Dr Robert Field, 49, reportedly contacted a friend in the last minutes of his life to say there was a "serious situation" involving a gunman inside his luxury penthouse in the city of Boston.

The London-born doctor was found dead together with his fiance Dr Lina Bolanos, 38. Sources said both were discovered tied up and had their throats slit.

Police called to the scene found an armed suspect still inside the flat, who was wounded after being shot by officers.

The man, named as Bampumim Teixeira, 30, was charged with two counts of murder on Monday from his hospital bed where he was being treated for three gunshot wounds.

A backpack containing jewellery, a replica firearm and at least one knife in the apartment, according to the district attorney's office.

Mr Teixeira had recently been released from jail after serving a sentence for attempting to hold up banks on two occasions, according to prosecutors.

Police Commissioner William Evans also said they "believe clearly" that murderer and victims knew each other, according to the Boston Globe.

According to reports, Dr Field was born in Hammersmith, west London, and the Massachusetts medical register said he graduated from Sheffield University's medical school in 1999.

The North Shore Pain Management centre, where he had worked since 2010, spoke of him as a "guiding vision" who gave patients and colleagues his "tireless devotion".

"His tragic and sudden passing leaves an inescapable void in all of us," the centre added in a statement.

Paying tribute, one patient wrote on Facebook: "He was an amazing Dr. who was so kind and compassionate.

"I always said if he ever moved back to England I would follow him. Dr Field changed my life."

The Foreign & Commonwealth Office has not confirmed his nationality.

His fiance Dr Bolanos worked at Massachusetts Eye and Ear hospital as a paediatric anaesthetist and was an instructor at the Harvard Medical School.

John Fernandez,the hospital's president, said: "Dr Bolanos was an outstanding paediatrican aesthetist and a wonderful colleague in the prime of both her career and life."

Mr Teixeira's lawyer, Steven Sack, has entered not guilty pleas to the two counts of murder over the killing in a hearing at South Boston Municipal Court and did not request bail.