LYNNFIELD – The sister of a Lynnfield woman who purportedly committed suicide under mysterious circumstances in the Virgin Islands earlier this month says she regrets not going along to the veterinarians’ conference as a traveling companion.Mary Elizabeth Baruffaldi of North Andover said Friday the fateful trip that ended in her older sister’s death might have had a different outcome had she gone along instead of her brother-in-law, Robert Harris.The couple landed in St. John on Nov. 4. In the wee hours of Nov. 5, Harris phoned relatives to inform them that his wife, North Reading veterinarian Joan Baruffaldi, was dead, the victim of a suicide carried out in the bathroom of their suite at the Westin Hotel.Harris, 47, told hotel security he and his wife had been arguing when she locked herself in the bathroom. According to Harris’ statement to island police, he heard a crash, waited about five minutes and summoned help because he couldn’t open the door.When security personnel arrived 10-15 minutes later, they helped him open the door. Harris said his wife apparently hanged herself using a bathrobe belt tied to the shower curtain rod.Boston attorney Donald McNamee, hired by Baruffadi’s first husband, Philip Klug of Medford, has been attempting to halt the cremation of the woman’s body so that another autopsy can be performed and perhaps shed additional light on the cause of death. Klug and Baruffaldi, divorced in 2000, shared custody of their two teenage children.Mary Elizabeth Baruffaldi is equally skeptical of Harris’ story, noting that it’s unlikely her sister would choose to travel to a beautiful Caribbean island with plans to attend courses linked to improving her veterinary practice if she intended to kill herself.”It just doesn’t make sense. Besides, the shower curtain rods in those hotels are designed to give way at 60 pounds. It wouldn’t have held her weight,” she said Friday. “When my sister told me she was going, I said, ‘Cancel the trip. I don’t want you going there with Bobby.’ I was just starting a new job so I couldn’t go along or I would have been the one with her. She didn’t want to go alone.”Baruffaldi and Harris, who married in December 2006, previously attended a veterinarians’ conference in Hawaii, the sister said, adding, “Bobby was the one who found out about going there and they did.”On Thursday, McNamee received a letter from Wilson J. Campbell, chief of the criminal investigations division in the Attorney General’s Office of the U.S. Virgin Islands, stating that Baruffaldi’s death is the subject of an ongoing criminal investigation by the Virgin Islands Police Department Major Crimes Unit.Last Oct. 2, Baruffaldi sought a restraining order against Harris after he allegedly attacked her in their 29 Robin Road home. Lynnfield police removed Harris from the premises. Harris moved to North Reading, where his parents and siblings live and work.The couple had argued bitterly over a series of emails between Harris and a female co-worker that Baruffaldi had discovered. Harris acknowledged having an affair with the woman, but claimed it preceded his second marriage.The Baruffaldi family was further incensed upon learning that Harris was allowed back into the Robin Road home to get some of his belongings after returning from the Virgin Islands. Harris was accompanied by Lynnfield police officers and at least one North Reading firefighter driving a North Reading Fire Department vehicle with the No. 5 as an identifying decal, Mary Elizabeth Baruffaldi said.Harris’ father, Nelson, is the former fire chief in North Reading. His brother, Tom, is the present fire chief and his brother, Richard, is a firefighter on the department.Given the circumstances, the pending criminal investigation and court fight over the autopsy, Mary Elizabeth Baruffaldi said the presence of Harris family members in the Lynnfield home seems improper and suspect. “What were they doing there, driving a public vehicle? They used a crowbar to break