Camacho, who authorities said is an illegal alien, was ordered held on $1 million bail at his arraignment Thursday.
The assaults took place along the Kensington Avenue corridor, the area where police said so-called "Kensington strangler" Antonio Rodriguez preyed on drug-addicted women last November and December.
Rodriguez was arrested in January and is awaiting trial in the deaths of three women. Police say he has confessed to the killings.
The recent investigation began Nov. 14, after one woman told police that she was sexually assaulted after she got into a man's car on Kensington Avenue near Somerset Street. On Nov. 22, two more women told police they were attacked several hours apart in the same area.
Tasha Jamerson, a spokeswoman for the D.A.'s office, declined to elaborate on the circumstances surrounding the fourth alleged attack, but court documents indicate it occurred Nov. 17 and involved an indecent assault.
On Tuesday, police traced the car to Camacho, who is said to live in Norristown, and brought him in for questioning.
Besides three counts of rape, Camacho is charged with aggravated assault, sexual assault, unlawful restraint, possession of an instrument of crime and related offenses, court records show.
His next court appearance is scheduled for Dec. 22.
When police searched for Antonio Rodriguez last year, they initially faced a challenge in gathering information. Many who frequent the neighborhood are involved in drugs or prostitution, said Philadelphia Capt. John Darby, head of the Special Victims Unit, and can be hesitant to approach police with information.
Some victims may not report crimes to police out of fear that they will be arrested, Darby said, and only come forward after learning of the existence of other victims.
"We've shown over and over again that we're ready, willing and able to investigate every single one of these cases," Darby said. "What we're trying to do is get a violent offender off the street, so every victim is important."
Contact staff writer Allison Steele at 215-854-2641 or firstname.lastname@example.org.
Staff writer Joseph A. Gambardello contributed to this story.