New details have emerged and charges have been filed in the love-triangle shooting that saw NYPD officer Yvonne Wu shoot her ex-girlfriend Jenny Li and the ex’s new partner, Jamie Liang on Wednesday.

A police source told the New York Post on Thursday that Wu, the off-duty cop, may have been clinging to hope that she and ex-girlfriend Li would reunite after a tumultuous break up.

When Wu saw her ex with her new lover, Jamie Liang, the police source believes she may have snapped.

Wu was arrested on Wednesday after authorities said she shot Li and Liang in a Bensonhurst, Brooklyn apartment. She was reportedly taken into custody without incident when she calmly told police that she had shot “someone.”

Jamie Liang, 24, died from at least one gunshot wound to the chest. The 23-year-old ex-girlfriend, now identified as Jenny Li, was taken to a nearby hospital for a gunshot wound but is expected to recover.

Wu was charged with murder and attempted murder on Thursday, though she was still reportedly undergoing a psychological evaluation at NYU Langone hospital in Brooklyn that night. It’s not clear if she’s been relocated to a city jail, or when she will be arraigned.

New Info on Breakup with Jenny Li

Previous reporting indicated that Wu and Li had split up three weeks ago, ending a two-year relationship. (The earliest reports claimed the couple dated for three years.) Sources originally suggested that the pair had maintained some contact, but that their conversations after the split were “confrontational.”

But the Post‘s police source on Thursday said that Wu might have had reason to believe she and Li would reunite, before she spotted Li with Jamie Liang sometime on or before Wednesday.

“She was still staying there on and off. She was still staying there some nights. It’s not that strange, maybe she thought it could still work out,” the source told reporters.

On Wednesday, police said they believed Wu was waiting in the apartment to ambush Li and Liang when they arrived, but they said they were not sure how the off-duty cop would have gained entry to the home. They told reporters they were investigating the possibility that Wu had broken in.

Authorities now say they believed Wu was waiting in the apartment “for hours” when Li and Liang returned to the home at around 5 p.m., at which point they believe Wu opened fire.

If the Post‘s other police source is correct — if Wu had been staying at the Bensonhurst apartment again since she and Jenny Li split up — then it’s possible she had a key, or otherwise would not have had to force entry.

Another police source told reporters Thursday that the frantic 911 call Li made during the attack contained disturbing audio of the shooting as it unfolded.

One woman can reportedly be heard shouting “I told you not to mess with me,” followed by another begging “No, please!” and then four gunshots, according to the Post.

Accused Cop was ‘Model Officer’

NYPD sources said Wu was a model officer, who always “exceeded expectations” in her annual performance reviews, and had received four medals in the course of her five-year stint in the department.

New information indicates Wu began her law enforcement career as a “NYPD Explorer,” enrolled in a youth program the department operates for New Yorkers ages 14 to 20.

The 31-year-old reportedly worked the graveyard shift out of the department’s 72nd precinct in Brooklyn and lived in Staten Island. She was reportedly scheduled to work the night she was arrested.

“This is a shock. Wu was a quiet, sweet person,” one police source told the Post. Another agreed that her arrest was “out of left field.”