Upper East Side Shooting: Azsia Johnson's alleged killer held without bail

The ex-boyfriend of Azsia Johnson, the 20-year-old mother who was shot dead as she pushed their infant daughter in a stroller has been ordered jailed without bail, with prosecutors describing the killing as a "premeditated execution."

Isaac Argro, 22, appeared Saturday evening in Manhattan Criminal Court on charges of second-degree murder and second-degree weapons possession.

Prosecutor Brittany DeCesare told Judge Eric Schumacher that on the night of the killing, Argro dressed in all black and wore a ski mask as he paced back and forth waiting to shoot Azsia Johnson, his estranged girlfriend.

"This case can only be described as a premeditated execution," DeCesare said, according to The New York Post. "The defendant persuaded the victim to meet after work and under the guise that he wanted to give the deceased items for their 3-month-old daughter."

Argro's defense attorney declined to comment.

Johnson was shot in the back of the head and killed as she pushed her 3-month-old baby in a stroller.

Johnson's mother had previously alleged that her daughter's ex-boyfriend was abusive and was stalking her after having the child.

Johnson, had been living in a domestic violence shelter on the Upper East Side when she was gunned down on Wednesday night at Lexington Avenue and 95th Street.

The 3-month-old in the stroller was not hurt, but was taken to a hospital for medical evaluation, police have said.

Authorities allege Argro called Johnson's family after the shooting to ask where his child was and threatened that another unidentified person was "next," the Post reported.

Argro is set to return to court Thursday.

With the Associated Press.