SAN LEANDRO (CBS SF) — A 21-year-old man has been arrested on suspicion of murder for the fatal stabbing of his father at an apartment complex in San Leandro Friday morning, police said.

Officers responded to a unit at the apartment complex in the 900 block of Juana Avenue at about 5:30 a.m. today after a neighbor reported that he heard a man calling for help, police spokesman Lt. Robert McManus said.

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When officers arrived at the apartment the 21-year-old man, who was covered in blood, opened the door for them, McManus said.

Officers detained the 21-year-old and then found the father, who appeared to be in his early 50s, suffering from stabbing wounds, according to McManus. The father was pronounced dead at the scene.

The 21-year-old, who wasn’t injured, was taken into custody at the San Leandro police department and will now be interviewed, according to McManus.

Investigators are trying to figure out what led up to the stabbing and why it happened, McManus said. He added that investigators may never be able to make sense of what happened.

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The father lived at the apartment unit and the son spent a lot of time there but it’s unclear if he lived there full time, McManus said.

Many family members of the victim and the suspect arrived at the apartment complex, which is located at the corner of Juana and Grand avenues after the stabbing but they declined to talk to reporters.

McManus said, “It’s a very sensitive situation because family members are learning that their father and husband was killed.”

He said, “There’s a lot of emotion.”

McManus said police aren’t releasing the names of the victim and the suspect yet because some family members still haven’t been notified about the fatal stabbing.

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