The man charged with stabbing a six-month pregnant woman last week in Perth Amboy later admitted stabbing her, and led detectives to the knife he used, detective wrote in a court filing.

Benny M. Pichardo Santos Arias, 25, is charged with murder and related crimes for the Nov. 8 slaying of Esmeralda Cedeno on a city street.

She was 20 years old. Her baby, a boy she'd named Avian, did not survive.

The City of Perth Amboy is in mourning for the tragic loss of former PAHS student, Esmeralda Cedeño and her unborn son, Avian. Please support her family during these difficult times. Posted by Randy Convery on Saturday, November 10, 2018

The Middlesex County detective, in an affidavit of probable cause, wrote that Santos Arias confessed to stabbing Cedeno and led police to a knife, which he'd hidden. One of the crime's he charged with is hindering his own apprehension.

Santos Arias said the stabbing was self defense. "His version has not been corroborated, either by witness statements or surveillance," the detective wrote.

Police obtained video footage in the investigation, but they did not say in the filing what exactly is shows.

The relationship between the suspect and victim, if any, was not described in the affidavit.

On a GoFundMe page raising money for her family, Cedeno - known as "Younge Chuchii" - is described as an ambitious, fearless young woman who's smile could light up a room and projected a happy vibe.

Santos Arias remained in the Middlesex County jail Friday, lodged under the name Benny Pichardo.

Kevin Shea may be reached at kshea@njadvancemedia.com. Follow him on Twitter@kevintshea. Find NJ.com on Facebook.