Daniels, 41, a 15-year veteran of the department who is assigned to the 22nd District in North Philadelphia, was indicted Thursday on 14 counts of illegally acquiring prescription painkillers.
"We believe he was passing fraudulent prescriptions to obtain oxycodone," Assistant U.S. Attorney Randall Hsia said after Daniels' initial appearance.
Hsia said that the alleged scam involved about 1,000 pills, likely for personal use. Prescription opiates can be highly addictive if abused.
Guarente said Daniels was aware that he was under investigation by the Drug Enforcement Administration. Asked if Daniels intended to fight the charges, Guarente would only say, "I anticipate a trial in this case."
Hsia said that others could be charged but that no other police officers were under investigation in the case. The pills were allegedly obtained at Rite Aid, ShopRite, Walgreens and other pharmacies in Philadelphia.
Daniels, who had been taken off street duty before Thursday's indictment, will be suspended by Commissioner Charles Ramsey with the intent to dismiss.
Contact William Bender at benderw@phillynews.com or 215-854-5255. Follow him on Twitter @wbender99. Read his blog at philly.com/DailyDelco.