PHILADELPHIA (WPVI) -- Philadelphia police are investigating six deaths in six separate incidents, with crime scenes in Southwest Philadelphia, North Philadelphia, West Philadelphia, Strawberry Mansion, Grays Ferry and East Falls.So far, police have identified four of the six victims and, Action News has learned, one of those who died was the younger brother of an NBA player.Over in the city's Grays Ferry section, 21-year-old Demetrius Pinckney was found dead in the 2300 block of Morris Street.Police say he was found with severe injuries to the head, with a green dirt bike nearby.Investigators also say a 20-year-old man was taken to the Hospital of the University of Pennsylvania by a private car, suffering a gunshot wound to the thigh and two gunshot wounds to the buttocks. He is listed in critical condition.Police say there was some type of argument or disturbance that led to numerous dirt bike and ATV drivers chasing each other, and several gunshots were heard by witnesses.Pinckney's death is being investigated as a homicide.Pinckney is the younger brother of Dion Waiters, who is a Philadelphia native.A man went on a stabbing rampage along a Southwest Philadelphia street, randomly attacking a person at a cellphone store, another inside a car, and killing a man at a mechanic shop, police said.Fifty-five-year-old Ronald Stanley of the 1100 block of South 58th Street is facing several charges including one count of murder and two counts of criminal homicide, aggravated assault, simple assault and related offenses.The violence began around 2:25 p.m. when, police say, a Stanley entered a Cricket Wireless store and stabbed a man in the chest who was paying his bill.The attacker then fled and climbed into a car and stabbed the driver in each hand.Stanley then allegedly headed to a nearby mechanic and stabbed 30-year-old Nathan Ackinson in the chest, who was watching repairs on his car. Ackinson collapsed in the road and later died from his injuries.The two other victims drove themselves to a hospital and were in stable condition.Homicide detectives are also investigating a deadly double shooting in North Philadelphia.It happened at 6 p.m. on the 2100 block of North Van Pelt Street. Police say 21-year-old Quadir Whitney was found dead with a gunshot wound the neck.A 22-year-old man survived a gunshot wound to the head and is in serious condition at Temple University Hospital.Police say an argument was the motive for the shooting, but did not release further details.At 8:15 p.m. gunfire rang out in the 1400 block of North Vodges Street in West Philadelphia.Officers arrived to find 22-year-old Trevor Bouknight suffering a gunshot wound. He was taken to the hospital but was pronounced dead.Investigators listed "drugs" as the motive for the shooting.Then around 8:30 p.m., a hail of gunfire killed a 31-year-old man in the 2400 block of North Hollywood in Strawberry Mansion.That man, Phillip Miller, was found in the street with multiple gunshot wounds. He was pronounced dead at the hospital.Police do not have a motive for the shooting.Lastly, at 9:30 p.m. a person was shot to death on the 3100 block of Abbottsford Avenue in East Falls The victim was discovered with multiple gunshot wounds to the body, head and face.Police have not yet identified the victim. A motive is unknown.