Suspected serial killer Jeffery Lee Guillory, described by a prosecutor as “cold through and through,’’ was convicted Sunday evening of second-degree murder in the 2002 strangulation of Renee Newman of Baton Rouge.

An East Baton Rouge Parish jury of six women and six men deliberated for just over 50 minutes before returning its unanimous verdict.

Prosecutor Dana Cummings said she was “pleasantly surprised’’ by how quickly the jury reached the verdict. She said strong DNA evidence played a big part in the swift guilty verdict.

East Baton Rouge Parish District Attorney Hillar Moore III said justice, albeit delayed, was served.

“This is the proper outcome,’’ he said.

Guillory, 45, faces an automatic sentence of life in prison. He will be formally sentenced Nov. 10.

Guillory’s lead attorney, Franz Borghardt, said an appeal will be filed after the sentencing.