Philly Cops Challenge Black College Student to Pickup Basketball Game — and Arrest Him

[Luminous Animal]

8. No. He was arrested. A person can be arrested without charge.

http://criminal-law.freeadvice.com/criminal-law/arrests_and_searches/arrest-detention.htm

Detentions and Arrests
An officer’s “brief and cursory” holding and questioning someone is a detention. An example is a cop stopping someone who is behaving suspiciously in order to ask a few questions. The suspect isn’t free to leave, but he also isn’t under arrest, at least until the officer develops probable cause. Another common example is an officer pulling over a driver for some kind of traffic or equipment violation.
An arrest, on the other hand, involves the police taking someone into custody through a more significant restraint on movement. The quintessential example involves the use of handcuffs and an advisement that the suspect is under arrest. (See How do I know if I’ve been arrested?)

http://www.nolo.com/legal-encyclopedia/arrest-vs-detention-how-tell-whether-you-ve-been-arrested-simply-detained.html