What began as a heated argument ended with a man stabbing the mother of his child and fleeing the scene with the toddler in tow, prompting a frantic citywide search that ended with his arrest Tuesday morning, Minneapolis police say.

Police said the victim was taken to the hospital with a stab wound to her leg. She is expected to survive.

Police later arrested 26-year-old Hershel Theo Hulbert, who allegedly stabbed his ex-girlfriend during a domestic situation on the 2000 block of 3rd Avenue S. near Franklin Avenue about 5:50 a.m.

According to officials, officers were called about 5:46 a.m. Tuesday to an apartment building in the 2000 block of 3rd Avenue S. on reports of a loud argument — over what is unclear — that started inside the apartment and later spilled onto the street.

Witnesses told police that Hulbert stabbed the woman in the leg, before taking the pair’s 2½-year old son and fleeing the scene in a silver 1999 Dodge Durango. The two had previously been in a relationship that ended, police said.

A police spokeswoman said that the victim was found at the scene, bleeding from a wound to her leg, and the father and son gone.

The state Bureau of Criminal Apprehension later issued an Amber Alert asking for the public’s help in locating the missing toddler, beaming the vehicle’s make and model to thousands of cellphones across the metro. The alert was also broadcast on the radio and on billboards.

The manhunt ended three hours later when investigators tracked Hulbert to a relative’s home, about one-and-a-half miles south of the apartment, according to police. The pair’s son was also found safe at the house.

A woman who answered the door Tuesday morning, identifying herself only as the child’s grandmother, said that the toddler was never in danger.

“He’s a good daddy and that’s all I’ve got to say,” the woman said. “He didn’t kidnap the baby: that’s his baby, too.”

Department spokeswoman Sgt. Catherine Michal credited the arrest to the quick-thinking of several 911 callers who witnessed the attack, as well as Hulbert’s “very cooperative family.”

“This was the very best possible outcome,” Michal told reporters at a morning news conference. “In moments like this, it is good to know that so many people are willing to participate” in helping find the missing child.”

Michal added that a second suspect, identified in the BCA alert as a man armed with a gun, had been located, but hadn’t been arrested.

By midday Tuesday, the police cruisers and crime-scene tape had vanished from outside the beige three-story apartment building, leaving no signs of the chaotic scene from earlier that morning.

Hulbert arrested on suspicion of second-degree domestic assault, a felony, but hadn’t been charged as of noon Tuesday.

Libor Jany • 612-673-4064 Twitter:@StribJany

Tim Harlow • 612-673-7768