Police spent about 13 hours Thursday trying to talk down off of a window ledge a Bronx man who alleged stabbed his girlfriend.

Rodolfo Jones, 49, who sources say was an NYPD traffic agent, allegedly used a butcher knife to stab his girlfriend in the neck and stomach in their apartment in University Avenue in University Heights.

When police arrived around 12:30 a.m., Jones got onto his window ledge several stories up, wearing only his underwear.

The stabbed woman was taken to St. Barnabas Hospital and is listed in critical condition.

Meanwhile, authorities say they spent more than half a day trying to talk Jones down from the ledge. They also set out an airbag, in case Jones fell or decided to jump.

At 1 p.m., Jones grew tired and policemen scaled down the building and helped him back through the window into his apartment. Jones then apologized for stabbing his girlfriend.

Officers said Jones suffered from fatigue and was in need of help.

“He was sorry he just snapped. It’s not his character, he’s a good guy,” said NYPD Sergeant Christopher Pupo. “He just went off the deep end. He just thought he was a bad person. He didn’t know why he did it.”

“That’s my neighbor. Very nice couple, never would think this would happen, they were two nice people,” said an area resident. “Every time I saw him, he would give me a handshake, good guy. The lady was good, beautiful lady. For me to see this, this is a shock.”

The case is reminiscent of Iman Morales, a 35-year-old emotionally-disturbed Brooklyn man in who was found standing naked on the edge of his building back in September.

Unlike Jones, Morales was Tased and fell to his death. Some police forces subsequently were ordered to take Taser and sensitivity training.

Onlookers approved of how the police handled the standoff with Jones and applauded when the man was safely inside.

“I was here for like six hours already, I missed my appointments to see the action take place,” said one local. “People talk about the police, that they’re very quick, and I don’t think so. They really take their time to help the people. Even though he’s a criminal, they gave him his rights and they protected him.”

Jones was taken to Jacobi Hospital and was not yet charged Thursday.