During Monday's hearing, Assistant District Attorney Branwen McNabb successfully argued for Watson to be held without bail while charges could be filed against in the new cases.
"Despite his likable social manner - and perhaps because of it - he presents a risk to children," McNabb stated, reading from a psychiatric evaluation of Watson prepared when he was released from juvenile detention at age 21.
Watson had at least once refused therapy for his crimes while in juvenile custody, McNabb said, and another time went AWOL.
The new information raises further questions of whether there were safeguards in place to prevent Watson - who lived with his mother across the street from William Dick School in North Philadelphia - from gaining access to children through youth recreational leagues.
This month, Watson was held on $500,000 bail after being charged with raping two brothers, ages 8 and 9, who played on a football team Watson organized for neighborhood children called the Little Vicks.
The brothers lived with Watson and his mother for about three months after their mother became homeless, police said.
Watson told investigators that the woman left her children with him because he was the "only one she could trust."
Prosecutors say Watson sexually assaulted the boys at least 10 times.
When child welfare officials arrived at the house in November, Watson tried to hide the children in an upstairs closet.
Since Watson's arrest, investigators from the Police Department's Special Victims Unit have been interviewing Little Vicks players and other children, including a 10-year-old and a 14-year-old who also lived with Watson and his mother.
McNabb said in court arrests were pending against Watson in three to five more cases of child molestation.
According to prosecutors, Watson was also a part-time coach for the Rhawnhurst Raiders football team from August of this year until October.
It is unclear if the Raiders - who play at the Pelbano Recreation Center in Rhawnhurst - conducted a background check on Watson.
Raiders team officials have not returned phone calls from The Inquirer, but have told other media that Watson was never formally associated with the team and only assisted at a few practices.
It also unclear whether a background check would have caught Watson's juvenile sexual offenses.
Tasha Jamerson, a spokeswoman for the District Attorney's Office, said that records of most juvenile offenses are sealed and would not surface on a background check conducted by the general public.
The Little Vicks do not appear to be part of any organized league. A team photo shows 11 children posing near a trash-strewn lot with the team name scribbled in marker across their T-shirts.