On Friday morning, the van was hijacked behind a pharmacy in Upper Darby.
The driver was tied up and left in the van in Philadelphia after it was ransacked.
That same day, Philadelphia narcotics officers working on another case raided a storefront and apartment on Buist Avenue. They found a large stash of prescription drugs inside.
As the investigation continued, five men were arrested: Curtis Brown, John Curley, Jamar Johnson, Antonio Martin and Salim Shabazz.
Later, the narcotics officers saw news coverage of the van hijacking. They checked the lot numbers on the drugs they confiscated, and they matched the ones missing.
They also found a distinctive hoodie with the word 'respect' on it. Police say it's the same one worn by one of the hijackers, a man they've identified as 39 year old Salim Shabazz.
He's facing muliple charges, and Upper Darby police expect to charge all five men being held by Philadelphia.
"We believe they're all responsible. Now it's a matter of building the case," said Superintendent Michael Chitwood of the Upper Darby police.
Police believe the suspects may also be responsible for a string of gunpoint drug store robberies in Delaware County.
Some of the drugs found in the Philadelphia raid also have lot numbers matching drugs stolen in one of the robberies.