A 20-year-old Maine man arrested in the death of a 14-year-old girl whose naked, charred body was found on a Brooklyn beach in January allegedly told police he smothered her with a pillow in his cousin's apartment because he thought she was pregnant, law enforcement sources said.

Christian Ferdinand, of Limestone, Maine, was charged Thursday with second-degree murder in the death of Shaniesha Forbes. The student at the Academy for Young Writers in Williamsburg disappeared two days before her body was found face up on the beach, with burns to her legs, arms and hands.

Ferdinand allegedly told detectives he exchanged phone numbers with Forbes in December after meeting her through Facebook. Over the next month, the two developed a relationship and had unprotected sex multiple times, sources say Ferdinand told police.

Ferdinand said he met Forbes on Jan. 4 at his cousin's apartment on Nostrand Avenue and she told him she was pregnant. They argued, and Ferdinand told detectives he killed Forbes, brought her body to the roof and hid it for a day before transporting it to Gerritsen Beach in a suitcase and setting her on fire, using Axe body spray as an accelerent.

The medical examiner has found no indication Forbes was pregnant, sources familiar with the investigation said.

Law enforcement sources say police recovered the suitcase Ferdinand said he used to transport her body. 

A law enforcement official previously told NBC 4 New York investigators had found a kerosene can and signs of a bonfire near where Forbes' body was found.

A review of Forbes' cell phone and Facebook information helped lead authorities to Ferdinand, law enforcement sources said. Police said Ferdinand had no prior record in New York.

Information on an attorney for Ferdinand wasn't immediately available. He's in NYPD custody. 

Forbes' family gathered on Gerritsen Beach last month to celebrate what would have been the teenager's 15th birthday. 

After Ferdinand's arrest, they surrounded themselves with pictures of Forbes and prayed for justice. They also urged other teenagers and their families to be cautious about who they communicate with online.