A Bronx man was charged Friday in the murder of his girlfriend — after he initially cast blame on a moped-riding duo who he claimed stabbed his gal pal while he relieved himself on the side of the road, cops and sources said.

Franklin Batallas was arrested at 1 p.m. and charged with murder, two counts of assault and criminal possession of a weapon in connection to the Wednesday night murder of Anthonella Contreras Linarez on City Island, police confirmed.

Police believe that Batallas stabbed Linarez repeatedly — but do not have a motive.  

The couple appeared to be deeply in love, and showed no signs of what would become their violent end, family and neighbors told The Post.

“He was, to us, a brother-in-law well loved. This was an emotional shock. I don’t know what to feel,” Linarez’s grieving sister, Mayker Contreras, said, adding that the family was planning funeral arrangements.

“My sister was a marvelous person. She loved everybody. She was my little girl,” Conteras said in Spanish.

“She loved to travel — to the Dominican Republic and wherever she was able to go.”

“Of course, her life was cut short.”

When asked what should be done about Batallas, Conteras said: “Let the law decide to keep him for all the time that the law permits.”

Batallas initially claimed that he and Linarez were on their way to dinner around 8:10 p.m. when the couple pulled over just outside Rodman’s Neck — allegedly because the man had to urinate, law enforcement sources said.

He claimed two men pulled up on a moped while he was doing his business, tried to rob Contreras Linarez and stabbed her multiple times when she resisted before they fled.

He said he then rushed back to the car and tried to stop the thugs, only to be slashed while trying to play hero, sources said.

Linarez, who was stabbed multiple times all over her body, was rushed to Montefiore New Rochelle Hospital, where she succumbed to her injuries, police said.

Batallas, who had a stab wound on his right forearm, was taken to the same hospital in stable condition before he was ultimately connected to the crime, police said.

Sources said the couple were together for three years, but a Facebook account for the alleged killer lists him as “single.”

A small memorial was set up outside Linarez’s Longwood apartment building Friday, complete with red and white roses and candles of the same colors.

Contreras Linarez had worked as a registered nurse at Mount Sinai Morningside hospital.

“The Mount Sinai Health System community is mourning the loss of one of our own,” a hospital spokesperson said Thursday. “We wish to convey our heartfelt condolences to family, friends and colleagues, and ask that you keep them in your thoughts.”

The couple had lived together at an apartment on Bathgate Avenue for about a year before they moved out eight months ago.

At the time, they appeared to be a normal couple who were friendly with their neighbors.

“They were always singing and dancing in the apartment,” said Angela Marcelino, adding that the music they listened to was “romantic.”

There was, however, about a month-long span when Linarez left the home, taking her small dog, Bella, with her.

“Sometimes I’d see Anthonella a little quiet and sad. I never asked her anything,” Marcelino continued.

“I don’t believe he did it but if I’m wrong, God forgive me. I’m hoping that he didn’t do it. He didn’t look like an aggressive person.”

Marcelino’s son, who asked not to be named, added: “When I heard what happened, I said, ‘No way! I don’t believe he did it. They looked like a nice couple.”