A man and a woman are dead Friday, after two separate homicidal incidents claimed their lives Thursday evening.

According to the San Francisco Police Department, officers were called to the 2000 block of Sutter Street, which is between Fillmore and Steiner Streets, at 9:25 Thursday evening.

When they arrived they discovered a 56-year-old woman who had been fatally attacked with a knife, they say, and who was deceased when they arrived. As of Friday morning, the San Francisco Medical Examiner's Office had not publicly identified the victim.

A 39-year-old man was arrested for the homicide, police say, but declined to give further details due to the pending investigation.

Homicide investigators were again called out at 11:53 p.m., this time to Mission Street and Geneva Avenue.

Police say that three suspects ā€” a 20-year-old man as well as two females aged 17 and 18 ā€” were in an as yet undescribed vehicle when one of them fired a handgun at a man in his early 20s and an 18-year-old woman.

Both victims were struck, and transported to San Francisco General Hospital. While the female victim's injuries are not life-threatening, police say that the male victim was pronounced dead at the hospital. As with Thursday's other victim, he has yet to be publically identified.

According to the SFPD, the suspects in the shooting were arrested. As the investigation is ongoing, police could not provide additional details on the case as of publication time.

These two deaths bring San Francisco's homicide count to 54, taking the city to the highest number of slayings since 2012. SF resident Nathaniel Burgess, who was shot on December 2 in the Bayview, died of his injuries on December 4, taking the total to 51. That makes Wednesday's as yet unsolved fatal shooting of Lisa Williams in the Mission District the city's 52nd. In comparison, there were 52 total homicides in SF at the end of 2015, 45 homicides in 2014, 48 in 2013, 68 in 2012, and 50 in 2011.

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