A mother of three small children was found slain in a stairwell of a Wheaton apartment building early Saturday and Montgomery County police obtained an arrest warrant for her boyfriend, charging him with first-degree murder, authorities said.

The victim, Marcello Rocio Nikaury, 37, was found dead shortly after 3:30 a.m. in a stairwell near her apartment in the 2200 block of Georgian Way, said Capt. Paul Starks, a police spokesman. He said investigators did not want to immediately disclose the manner in which she had been killed. Her three children, whose ages were not immediately clear, were in the apartment, unharmed, Starks said.

“They did not witness the killing or see the deceased,” he said.

Because the only easy way out of the building from the apartment is by way of the stairwell where detectives were examining the woman’s body, the youngsters were told that there had been a fire in the building and they were taken out by police officers using a ladder, Starks said. They were turned over to child-welfare workers.

The suspect, Matire Puente-Fulcar, 31, was involved in a romantic relationship with Nikaury, police said. The killing allegedly stemmed from a domestic dispute.

The suspect, Matire Puente-Fulcar, 31, was involved in a romantic relationship with the victim, police said.

Police described Puente-Fulcar as 6-foot-1, about 190 pounds, with short black hair. They said he was last seen wearing tan pants and an orange shirt and driving a late-model Ford Edge with the temporary license plate T558404.

Police asked anyone with information on his whereabouts to call the major crimes division at 240-773-5070. Those wishing to remain anonymous can call Crime Solvers of Montgomery County at 866-411-8477. Police offered a reward of up to $1,000 for information leading to an arrest or indictment in the case.