The Massachusetts Appeals Court today upheld a Dorchester man’s conviction for stabbing a co-worker to death at a Copley Place restaurant kitchen, Suffolk County District Attorney Daniel F. Conley said.

The Appeals Court affirmed IVAN LORENZO SOSA’s involuntary manslaughter conviction stemming from the Sept. 15, 2006, stabbing death of 39-year-old Carlos Borrero, Jr., in the Turner Fisheries Restaurant at Copley Square’s Westin Hotel, where both men worked. The fatal injury was a stab wound that penetrated the victim’s right lung, causing him to bleed to death.

Sosa (D.O.B. 5/14/69) was convicted of that offense after his 2008 trial, receiving a sentence of eight to 12 years in state prison. Members of Conley’s Homicide Unit proved at that trial that Sosa stabbed Borrero four times as the dinner shift got under way. The fatal injury was a stab wound that penetrated the victim’s right lung, causing him to bleed to death.

Prosecutors introduced evidence that Sosa blamed Borrero, who was once a friend, for his failure to win the heart of a female server who also worked at the restaurant.

Sosa claimed self-defense and testified that Borrero had struck him with a metal bowl and charged at him with a knife. On cross-examination, the trial prosecutor asked him whether he’d told anyone about that alleged assault, and Sosa said he had not. On appeal, Sosa claimed that the inquiry was unfair.

“The defendant claims that the prosecutor’s cross-examination ran afoul of the proscription against the use of a defendant’s post-Miranda silence to impeach him,” Justice William J. Meade wrote in a seven-page decision. “We disagree …. Here, as clarified by the prosecutor, the defendant failed to mention the victim’s bowl and knife attack to his coworkers when he was asked about the stabbing. This omission or silence occurred prior to his arrest and prior to his being advised of the Miranda warnings. The due process prohibition in [a 1976 US Supreme Court case] neither contemplates nor extends to impeachment of a defendant with his pre-Miranda silence.”

Assistant District Attorney Kris Foster of the DA’s Appeals Division argued in defense of the conviction. Assistant District Attorney Ian Polumbaum prosecuted the case at trial. Sosa was represented on appeal by attorney David Skeels.