A man charged with murdering his former teacher and their 4-year-old son was angry that the boy was being dressed in girls' clothing, NYPD Chief of Detectives Robert Boyce said on Wednesday.

Police said Isaac Duran Infante, 23, was charged Tuesday with two counts of first-degree murder and two counts of second-degree murder, one day after Felicia Barahona, 36, and 4-year-old Miguel Barahona were found dead in their Harlem apartment.

Duran Infante, who lives in Bethlehem, Pennsylvania, with a new girlfriend, admitted that he went to the apartment with the intention of killing his former lover; he later decided to kill the boy as well, Boyce said. 

Duran Infante felt antagonized by Barahona because she was dressing Miguel in girls' clothing, Boyce said. There were also monetary motives behind the killings, he said.

Duran Infante was arraigned Wednesday afternoon before Judge Ushir Pandit-Durant, and he was ordered to be held without bail, pending the continuation of the case on Friday.

Barahona's body was found on the living room floor with an electrical cord around her neck, according to police, who said her son was found underwater in the bathtub. Duran Infante had choked the boy with a wire before putting him in the tub, Boyce said. The medical examiner's officer later ruled that the two had been killed by strangulation with a cord, according to the criminal complaint against Duran Infante.

Duran Infante later told police that he had killed the mother and son by placing a cord around their necks and squeezing until they stopped breathing, according to the criminal complaint filed against him. 

He was seen entering Barahona's apartment building on surveillance camera at about 9:13 p.m. last Thursday and leaving the building hours later at about 12:27 a.m., according to the complaint.

Barahona and her son were discovered by the building’s super after someone noticed an odor coming from the apartment.

Barahona was fired from her job as a teacher at the DeWitt Clinton High School in the Bronx after she became pregnant by Duran Infante, then 18, following a four-month affair that started in 2011. Barahona reportedly discouraged the teen from using protection.

- With Jillian Jorgensen