NEW YORK (CBSNewYork) – The NYPD has released new surveillance video of a man accused of shooting a Bronx mother to death through her peephole.

The man can be seen wearing a mask and carrying an umbrella as he walked down the hallway of an apartment at 760 Grand Concourse in the Bronx around 10 p.m. Saturday. He walks away, then returns to unit 1F.

That’s where police say he fired through the peephole, killing 45-year-old Wendy Martinez, who lived there with her two sons.

“She’s like the best person. It’s really hard to understand,” her coworker Namdi Akoro said.

(credit: Facebook/Wendy Martinez)

When emergency responders arrived, they found Martinez lying inside the apartment with a gunshot wound to her face.

Police said her 15-year-old son called 911 and crouched inside a closet.

Private investigator Manuel Gomez, of Black Ops Private Investigators, told CBS2 he was looking into a nearly four-year-old murder case that was connected to Martinez’s oldest son, 25-year-old Briano Solano.

“I know the family was receiving death threats for two years – over two years,” he said. “She was an innocent woman, a mother of two who worked for the community, well respected, worked in the hospital, served the community.”

Police do not believe Martinez was the intended target. They said the suspect could have been going after someone else in the household.

Investigators described the suspect as being in his 20s, last seen wearing a dark jacket and dark sweatpants with a Miami Heat basketball logo on the left leg.

NYPD Crime Stoppers are offering a $2,500 reward for information leading to an arrest and conviction in the case.

Anyone with information about the shooting is asked to call the NYPD’s Crime Stoppers hotline at 1-800-577-TIPS (8477), or 1-888-57-PISTA (74782) for Spanish. The public can also submit their tips by logging onto the Crime Stoppers website, on Twitter @NYPDTips or by texting them to 274637 (CRIMES) then enter TIP577.