DeCoatsworth had been under investigation by the Special Victims Unit after two women alleged that he forced them to use drugs and engage in sexual activity.
The women said they came into contact with DeCoatsworth about 2 a.m. Thursday at a party, said Officer Christine O'Brien, a police spokeswoman. They left the party with him, and the three went to another location.
Police did not identify the site of the party or say where the alleged crimes took place.
At the second site, DeCoatsworth took out a handgun and allegedly forced the two women "to engage in the use of narcotics and sexual acts," O'Brien said.
The women reported the incident to police, and DeCoatsworth was charged with rape, sexual assault, terroristic threats, and related charges. His bail was set at $60 million.
The women told police DeCoatsworth had held them captive for two days, according to the law enforcement source.
It was a long fall from grace for the former officer, who in 2007 was lauded as a hero.
As a 21-year-old rookie, DeCoatsworth took a shotgun blast to the face and, bleeding heavily and returning fire, pursued his attacker for several blocks before collapsing and radioing for help.
The gunman, Antonio Coulter, was caught and later pleaded guilty in the shooting. DeCoatsworth underwent extensive surgery and returned to duty in June 2008.
His heroism in that case led to an invitation to sit next to the first lady during the president's 2009 address.
DeCoatsworth then became involved in two controversial incidents in which he shot at suspects. In April 2009, he shot Anthony Temple when the man lunged for his gun, police said, and a backup officer then shot and killed Temple.
The following September, he wounded a man in a leg who allegedly ran at him on a motorcycle.
DeCoatsworth racked up a number of Internal Affairs complaints, and he retired in December 2011 at age 25. He left, a police spokesman said at the time, due to injuries from the 2007 shooting.
'Something like this'
Some in the Police Department had feared DeCoatsworth was badly troubled. One officer said DeCoatsworth's unpredictable behavior and temper had led some in the department to view him as a time bomb.
"I hate to say it, but I did see something like this coming," the officer said Saturday.
Neighbors at a diner down the block from DeCoatsworth's home said he had been known to behave erratically. A woman who asked not to be named said she avoided the former officer after an incident in the fall in which his pit bull allegedly charged at her chihuahua.
"From the look in his eyes," she said, "I was terrified."
Shattered glass from DeCoatsworth's door spilled out over his front steps Saturday afternoon, and people inside refused to answer the door. When two people left the apartment, they declined to comment.
Contact Jonathan Lai
at 856-779-3220, firstname.lastname@example.org, or follow on Twitter @elaijuh.
Inquirer staff writer Allison Steele contributed to this article.