Three people, including two Mummers, were killed and a fourth person was critically injured early Wednesday when their SUV was hit head-on in South Philadelphia by a car driven by a possibly suicidal man who appeared to have self-inflicted stab wounds.

Police said the car’s driver, Keith Campbell, 29, who has numerous addresses in Delaware, may have stabbed himself 15 to 20 times in the chest and stomach before crashing into the other vehicle. He remained in critical condition Wednesday night at Thomas Jefferson University Hospital.

Police Capt. Mark Overwise, commander of the Accident Investigation District, said the four victims in the SUV apparently were returning home from a party at the South Philadelphia String Band clubhouse when the crash occurred about 1:45 a.m. on the 600 block of Packer Avenue, near the stadium complex.

Overwise said Campbell was driving a 2014 Audi A4 west at a high speed when he crossed the center line and slammed into an eastbound 2015 Acura RDX.

Killed were Joseph Ferry, 36, of South Philadelphia, the driver of the SUV; Kelly Wiseley, 35, of Glenolden; and Dennis Palandro, 31, of Morton, police said. Palandro’s 30-year-old wife suffered numerous injuries and was in critical condition at Jefferson.

Ferry and Palandro were members of the South Philadelphia String Band, which came in second in its category at Tuesday’s Mummers Parade. Palandro was the son of Denny Palandro, the band’s captain. Wiseley was the daughter of retired Folcroft Borough Police Sgt. William Wiseley, the department said in a tweet Wednesday evening.

The string band said in a statement its members were “deeply saddened at the loss of our family members” and requested privacy.

Ferry and Wiseley got engaged at Christmas, 6ABC reported.

On Wednesday night, black bunting was draped on the band’s clubhouse sign. Decorations from Tuesday’s parade were on display outside the clubhouse, located at Donaghy Hall, 2820 W. Porter St., between I-76 and the Schuylkill.

Police were awaiting a search warrant for Campbell’s car to see whether alcohol or drugs were factors in the crash or if there was any other evidence to explain what happened.

Police did not know Campbell had been stabbed until after he arrived at Jefferson and was examined by doctors.

Officers at the crash scene later found a 10-inch knife in the Audi’s front seat area, police said.

Overwise said police did not know whether Campbell was conscious when his Audi collided with the SUV.

Investigators were seeking any surveillance video from the area that might have captured the crash.

Campbell was facing four counts of causing an accident that resulted in death or serious injury and could face additional, more serious charges after the investigation is completed, Overwise said.

Staff writer Robert Moran contributed to this article.