A man behind bars for the strangling murder of his wife was sentenced Tuesday to more jail time for the raping and killing of a Bronx teenage girl.

James Martin, 42, pleaded guilty in court to the 1998 raping and killing of 14-year-old Marleny Cruz. He will be serving an additional 20 years for her murder.

Martin's semen was found inside the Bronx teen when she was discovered dead on Valentine Avenue 18 years ago.

In 2011, detectives were able to match the evidence to Martin thanks to advancements in DNA technology. They then questioned him in a Pennsylvania prison, where he was already serving time for the 2005 strangling murder of his wife.

Prosecutors say that although Martin claimed the sex between he and Cruz was consensual, at the time of her death, Martin was 24 years old and Cruz was 14 years old.

They say Cruz had a troubled home life, running away from her foster home in Yonkers only to be found on the street with her face beaten in.

Prosecutors say in total, Martin has committed three different murders - the first was in 1989 when they say he strangled a high school classmate to death to steal his sneakers.