ROCKLAND — A Rockland man has been convicted of killing his ex-girlfriend.

A jury in Knox Superior Court found 37-year-old Arnold Diana guilty of murder after about four hours of deliberations on Thursday.

The state’s medical examiner said 48-year-old Katherine Windred died of strangulation in November 2010. Prosecutors said she was killed in Diana’s apartment while her 11-year-old son was waiting outside in her car reading comic books.

Diana will be sentenced later this year. He faces a maximum sentence of life in prison and a minimum of 25 years behind bars.

Prosecutors said there was overwhelming evidence that Diana killed Windred after finding out that she had met another man.