Police said Wednesday that the man suspected of killing his girlfriend at a ritzy Hamptons spa was found dead in Pennsylvania after he turned a gun on himself.

Suffolk County police said Thomas Gannon, 56, was found with the fatal bullet wound at his home in Honesdale, Pennsylvania, over 200 miles from the Long Island resort where 33-year-old Sabina Rosas was slain on Monday.

New York authorities said the female artist’s remains were found in one of the guest rooms at the Shou Sugi Ban House, a boutique vacation spa that has hosted celebrities such as Katie Couric and Kate Hudson in the past.

Police haven’t publicly said how Ms. Rosas was killed. They also said Mr. Gannon and the victim knew each other, but didn’t describe the nature of their relationship.

“We are not confirming the relationship, but we can say it was domestic in nature,” a Suffolk County police spokesperson said.

The Daily Mail reported that the victim and Mr. Gannon were romantically involved, after the publication spoke with her unnamed fiance and with her mentor Liz Phillips.

Ms. Rosas’ family said she leaves behind her parents and three sisters, as well as her fiance and her separated husband.

“Sabina deserves justice, and we were seeking accountability for her death,” the family said in a statement. “The loss of the suspect means we will never hear the truth about what happened to her. This outcome has robbed us of the opportunity to find closure through the legal process.”

Ms. Rosas was born in Tajikistan and moved to the U.S. in 2009.

• Matt Delaney can be reached at mdelaney@washingtontimes.com.