A 23-year-old man suspected of decapitating his grandmother inside her Northern California home and Thomas Caldwellthen leaving with her head has been arrested and charged with her murder, police said.

Investigators had named Luis Aroyo-Lopez as the man suspected of being behind what they said was a "targeted attack" in Santa Rosa on a 64-year-old woman, who was later identified as his grandmother. Aroyo-Lopez was taken into custody Saturday in San Francisco two days after officers responding to reports of a possible homicide found the headless body of Elvia Lopez-Arroyo, Santa Rose police said in a news release shared on Facebook.

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Aroyo-Lopez flees scene, sparks two-day manhunt

Homicide detectives began investigating shortly after officers arrived Thursday afternoon at the Santa Rosa home and discovered the grisly scene.

The woman's head was not found at the home, and investigators later determined that her grandson had likely left with it in his possession when he fled the residence on foot, police said.

After Aroyo-Lopez was identified as the prime suspect, a manhunt involving U.S. Marshals unfolded to track him down.

The search came to an end Saturday when an officer with the San Francisco Police Department recognized Aroyo-Lopez from wanted person bulletins at a downtown transit station and arrested him, according to Santa Rosa Police. Custody of Aroyo-Lopez was soon transferred to Santa Rose police, who booked him into the Sonoma County Main Adult Detention Facility.

Investigators also reported seizing multiple weapons at the Santa Rosa home, which they said will need to be examined before any can be identified as the one used in the homicide.

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Victim's head found near Santa Rosa creek

The victim’s head was found Saturday evening on the south bank of the Santa Rosa Creek. It was brought to the Sonoma County Coroner's Office so that officials could identify the woman as the suspect's grandmother.

Prior to the homicide, Aroyo-Lopez had recently been released from California prison where he had served time after being convicted for assault with a deadly weapon and weapons possession. The charges were unrelated to the victim in the homicide, police said.

In addition to the murder charge, Aroyo-Lopez has also been charged for suspicion of violating the terms of his post-release control and was denied bail. He remains in-custody while awaiting the resolution of his case in court.

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at [email protected]