
A 47-year-old man was stabbed to death in his Harlem apartment, police said Monday — and his girlfriend was taken into custody for questioning.
Alejandro Santos was knifed in his sixth-floor apartment on W. 147th St. near Frederick Douglass Blvd. about 3:40 p.m. on Sunday, cops said.
One neighbor said she heard piercing screams followed by the victim’s girlfriend pounding on neighbors’ doors and begging someone to call 911.

The neighbor said she made that call, then listened through her door as the woman told first responders Santos had stabbed himself.
“She was very adamant,” the neighbor said. “She said from the beginning he did it to himself.”
“I can’t imagine someone would stab himself multiple times,” the neighbor added.
Police said Santos was unconscious with multiple stab wounds all over his body when officers got to the scene. Medics rushed him to Harlem Hospital, but he could not be saved.
The victim’s girlfriend was taken into custody and was being questioned at the 32nd Precinct stationhouse, but had not yet been charged, police said.

Brandon Cone, 29, was in his fifth-floor apartment with his wife and 3-year-old son when he heard screaming from the floor above.
“Originally I thought she had been stabbed,” Cone said of the victim’s girlfriend. “She was covered in blood. … As soon as I saw that I ran back inside and called 911.”
Cone’s wife, Jeneve Cone, who showed the Daily News cell phone video depicting the blood trail the girlfriend left behind as she ran down one flight to Cone’s floor, said it was nothing new to hear shouting matches coming from the victim’s apartment.
“They were loud a lot but nothing like this,” she said. “You would hear things get loud. It was a bad loud.”