US mother accused of killing her toddler son as he was interfering with her affair

A US mother has been accused of killing her toddler son.

Heather Reynolds from New Jersey allegedly smothered the 17-month-old Axel in May 2018, covering his mouth and nose with a wipe because she allegedly felt he was interfering with her extramarital affair, prosecutors claim according to NJ.com.

The 41-year-old appeared in court on Tuesday. Assistant Prosecutor Peter Gallagher labelled the killing "an absolutely brutal murder" also saying the toddler was a "helpless victim".

The prosecutor also detailed alleged text messages alluding to her frustration about her "boyfriend's apparent lack of interest".

“A review of the text messages between the defendant and her boyfriend from the previous night reveal that the defendant was becoming frustrated by the boyfriend’s apparent lack of interest,” Gallagher stated.

“And witnesses also told detectives that the defendant had expressed the sentiment that her toddler son … was an obstacle to her relationship with her boyfriend.”

On the night of Axel's death, witnesses allegedly claimed Reynolds had been using methamphetamine. According to Gallagher, police also found residue of the drug in her bag.

However, Reynolds' attorney, Michael Testa Sr. has insisted she is innocent.

"She adamantly denies that she has anything to do the death of her child," he said.

Reynolds has pleaded not guilty to all charges of murder, endangering the welfare of a child and possession of methamphetamine, NJ.com reports.

It was ruled by the judge Reynolds would remain in custody until the official trial. If she is found guilty she faces up to life in prison.